Answer:make sure the temperature equilibrium exists between flask and acrylic
Explanation: It is fundamental after packing acrylic resin into the denture flasks, one should wait to cure the resin to "make sure the temperature equilibrium exists between the flask and acrylic".
To ensure the optimal curing of acrylic resin in the denture flasks, it is necessary to follow appropriate procedures that are similar to the curing or solidifying processes in other laboratory settings. After packing the acrylic resin into the denture flasks, the resin typically requires a certain period of time to cure. This process is akin to allowing gels to solidify in biological experiments or epoxy diane resins to cure in polymer chemistry contexts.
In these scenarios, specific times are often recommended to achieve complete solidification or curing. For instance, gels may take about 20 to 30 minutes to solidify after setting, and an epoxy resin could require measurements at intervals from 5 to 20 minutes during its curing process.
1.)What caused the change in water quality in Flint, Michigan?
The city was taken off the Detroit water system to save money.
City officials decided to stop fully treating the water to save money.
The Flint River became contaminated which caused lead to get into the water.
City officials ignored the Clean Water Act and allowed wastewater to be dumped into the river.
2.)What is graywater?
household wastewater except for the wastewater from toilets
household wastewater that does not contain surfactants
all wastewater generated from household usage
wastewater generated from indoor household usage
3.)Which data help hydrologists predict floods? Select the two correct answers.
impermeable land area
nitrate levels
water temperature
dissolved oxygen
snowpack
4.)Which of the following water filtration methods requires the use of a membrane or filter?
reverse osmosis
ultraviolet radiation
distillation
chlorination
5.)Which of the following courses should a student take in order to become a hydrologist? Choose the three correct answers.
statistics
geography
coding
physical science
philosophy
chemistry
Answer:
1. The answer is (A) The city was taken off the Detroit water system to save money.
2. The answer is (A) household wastewater except for the wastewater from toilets
3. Impermeable land area and snowpack
4. Reverse osmosis
5. geography , chemistry and statistics
Explanation:
1. The answer is (A) The city was taken off the Detroit water system to save money.
Flint water is located in the flint city, Michigan. The Flint water crisis is a communal health issue that occurred five years ago. The flint water changed its source from the treated Detroit Water and Sewerage Department water to the Flint River which resulted in the killing of 12 people and infected 87 people with water disease. The cause of its change was a result of the money taken off the Detroit water system to save money.
2. What is graywater?
The answer is (A) household wastewater except for the wastewater from toilets
3. Which data help hydrologists predict floods?
Impermeable land area
Snowpack
Impermeable land area, and Snowpack
The factors listed above are very important in helping a hydrologist to predict floods. There also other factors such as topography, drainage and many more to make the forecast rightly.
4 the answer is Reverse osmosis
A filtration using a semi-permeable membrane that has small pores that are adequate to move through the molecule of pure water and avoid solvents and germs from entering is called Reverse Osmosis
5. The study of Chemistry has to do with the chemical response which is also required to know the chemical response in Water by a hydrologist. The study of geography deals with the study of the earth which water is inclusive, also statistics is required to understand the importance of parameters when compared with one another
Water is the abiotic factor that got deteriorated in Flint, Michigan because the city was taken off the Detroit water system. Thus, the correct options are 1. A, 2. A, 3. A and E, 4. A, and 5. A, B, and F.
Who are hydrologists?Hydrologists are the people that study and analyze the water and its quality. The water quality in Flint, Michigan changed because the city was removed from the Detroit water system. Hence, option A is correct.
Graywater is household water that gets released from the houses but does not contain the water released from the toilets. Hence, option A is correct. The data from the impermeable land area and snowpacks helps the hydrologists to predict the flood conditions. Hence, options A and E are correct.
The process of reverse osmosis uses the filter and the membrane as the water filtration method. Hence, option A is correct. To become hydrologists the students should take up statistics, geography, and chemistry as the subject. Hence, options A, B, and F are correct.
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Within the light organ, bacteria are protected and nourished, and rapidly increase in number. At night, they provide the light needed for counterillumination. But by dawn, as the squid prepares to hide in the sand for the day, it ejects about 95% of the bacteria from the light organ. Which of the following is the LEAST likely explanation for why eliminating 95% of the bacteria present in the light organ is necessary?
Answer:
At dawn the squid prepares to hide in the sand for the day and it ejects about 95% of the bacteria from the light organ in order to reduce or stop the growth of bacteria population in the squid. This will prevent the bacteria population from reaching a level too high for the squid to support.
Which of the following is true of female genital mutilation? like male cisrcumscision it does not retrict the ability to experience?
Answer:
Child birth complication, low self esteem, urinary problems, reduced satisfaction etc.
Explanation:
Female genital mutilation is a procedure carried out on female reproductive organ, cutting out partially or totally, the external part of the organ. It has no medical benefit and it is practiced in most African countries.
There are different types of female organ mutilation, namely; cutting, piercing, scraping, cauterization etc.
There are so many disadvantages of mutilation, they are;
urinary problem.
child birth complications.
Intercourse problems ( reduced satisfaction).
psychological problems.
Female genital problems.
menstrual problems etc.
Females who lift weights are not going to develop large, bulky muscles because __________. A. they have more muscle fibers than men B. they have thicker muscle fibers than men C. they have lower testosterone levels than men D. all of the above Please select the best answer from the choices provided. A B C D
Answer: C. they have lower testosterone levels than men
Explanation:
Although testosterone is a male sex hormone but it can be secreted by the ovaries and adrenal glands of females. The testosterone is responsible for increase in muscle mass and increase in strength in both males and females. In females the level of testosterone remains lower than men hence, the muscle mass in females is not bulky.
Answer:
C
Explanation:
The guy below above explained it perfectly
Which of the following people most likely got cancer because of environmental factors?
A) A 36-year-old man with brain cancer.
B) A 67-year-old man with prostate cancer.
C) A 52-year-old woman with bone cancer.
D) A 47-year-old woman with lung cancer.
Answer: option D - (A 47-year-old woman with lung cancer.)
Explanation:
Cancer is a disease in which the cells of a tissue undergo uncontrolled (and often rapid) proliferation. It can be caused by factors ranging from genetic defects to environmental or lifestyle patterns to microbial infections, radiation exposure etc.
Lung cancer largely occurs when an organism is exposed to environmental factors such as pollutants in the air, soil or water. Also, unhealthy habits such as smoking cigarettes, tobacco are highly implicated.
Note, UNLIKE Lung cancer, other kinds of cancer mentioned have stronger genetic basis
Identical, or monozygotic, twins develop from a single egg fertilized by a single sperm. Monozygotic twins are genetically identical because they originate from a single zygote that split into two. Caroline Lost and her colleagues examined nine measures of social, behavioral, and cognitive ability in 1000 pairs of both male and female identical twins. Their study found that pairs of male twins tended to be more alike in their prosocial behavior, peer problems, and verbal ability scores than pairs of female twins. Which of the following choices explains this observation? s on the X and Y chromosomes in the brains of males results Interacting g in identical twins with more similar behaviors Identical male twins express the same X-linked alleles in their neural cells because males undergo random X-inactivation Male twins have similar expression levels of X-linked genes, because the Y chromosome silences expression of X chromosome genes Q Females are mosaic for the expression of heterozygous X-inked loci because females undergo random X-inactivation
Answer:
The correct answer is "Females are mosaic for the expression of heterozygous X-inked loci because females undergo random X-inactivation".
Explanation:
This study reports that pairs of male twins tended to be more alike in their prosocial behavior, peer problems, and verbal ability scores than pairs of female twins. This is explained by the process of random X-inactivation in pairs of female twins. Random X-inactivation is the transcriptional silencing of one X chromosome in female cells during its development. This results in pairs of female twins being mosaic for the expression of heterozygous X-inked, making female twins actually not identical in its phenotype.
Final answer:
The observation that male identical twins are more alike in certain behaviors and abilities is potentially due to males uniformly expressing X-linked genes, whereas females show variations in expression due to X-inactivation, leading to a mosaic expression of X-linked genes.
Explanation:
The study mentioned in the question observed that pairs of male identical twins exhibited more similar prosocial behavior, peer problems, and verbal ability scores compared to pairs of female identical twins. A possible explanation for this observation is related to the phenomenon of X-inactivation. In females, one of the two X chromosomes present in each cell is randomly inactivated, which leads to mosaic expression of X-linked genes. Since each cell randomly inactivates one of the X chromosomes, the expression of X-linked genes can vary across different cells, potentially leading to more variability in certain traits among female monozygotic twins.
In males, however, there is only one X chromosome to express X-linked genes. This results in males having more consistent expression levels of these genes across cells. Since male monozygotic twins both have the same Y chromosome and the same X chromosome, the expression of these genes will be very similar between the two, potentially leading to more similar behaviors and abilities.
The following sequence of double stranded DNA encodes a hypothetical protein called GEN in a bacteria. Transcription starts at and includes the C-G base pair in Bold. The underlined T-A base pair indicates the transcription terminator. 3' -AAGCGGATACCTCCCAGTAGATGCTCCGGGGCTAGTGATTTCGAAC-5
A) What are the first 9 bases of the transcribed RNA? Be sure to label the 5' and 3" ends of the RNA 5' CCCCUAUGG3'
B) What are the first 4 amino acids of the subsequent polypeptide? Be sure to label the N- and C- termini. N-MET-GLU-GLY-HIS
C) How many amino acids long is the GEN polypeptide? 10 AMINO ACIDS
D) You identify a strain of bacteria containing a mutant tRNA that is capable of adding a tryptophan residue when it recognizes the stop codon UAG in the mRNA. The GEN polypeptide would be (longer, shorter, the same) in the presence of the mutart (nonsense suppressor) Trp tRNA?
Answer:
A) AUG GAG GGU
B) N-MET-GLU-GLY-HIS
C) 10 amino acids
D) The stop codon here is UAA, instead of UAG. If a tryptophane residue is added where the stop codon is, the GEN polypeptide would be longer
Explanation:
First we must obtain the the complementary chain or mRNA
A) AUG start codon is complementary to DNA TAC triplet, and GAG is complementary to CTC, and GGU to CCA (running from left to right towards 5'DNA direction (AAGCGGATACCTCCCAGTAGATGCTCCGGGGCTAGTGATTTCGAAC-5)
B) TAC corresponds to Methionine, GAG to Glutamate, GGU to Glycine, and CAU to Histidine
C) UAA is the stop codon, that is complementary where the DNA triplet is ATT. From AUG to UAA, we can have 10 amino acids transcribed
D) If a trp is included where the stop codon is UAA, then the mRNA would be longer with a consequent traduction of a longer GEN polypeptide
A 60-year-old woman is experiencing vertigo. She ignores the symptoms initially, but now her attacks are accompanied by severe nausea and vomiting. Following an attack, she hears a roaring in her ears that causes temporary deafness for some time after. What do you think her problem is, and what is its suspected cause?
Answer:
Meniere's syndrome
Explanation:
Meniere's syndrome is a disorder of the inner ear that can lead vertigo and hearing loss and commonly affects only one ear. The cause of this disease is unknown however, it is associated with an abnormal amount of fluid in the inner ear.
The roaring noise in her ear is called tinnitus which is a symptom of vertigo
Which of the following statements about olfactory receptors is false?
Select one:
a. They are bulb-like structures at the tip of the frontal lobe where the olfactory nerves begin.
b. They are cells.
c. They are located in a mucous membrane at the top of the nose.
d. They have small, hair-like extensions.
Answer:
They are bulb-like structures at the tip of the frontal lobe where the olfactory nerves begin. (Ans A)
Explanation:
Olfactory receptors which are also known as smell receptor, and present in the cell membrane of olfactory receptor neurons. They are the proteins which are capable of binding with odour molecules which play an important role in the sense of smell.
Each receptor of olfactory cell contains a single external process which extends to the surface which is found in the epithelium, and gives rise long, slender extensions know as cilia. Mucus of the nasal cavity covered the cilia, and facilitating the detection of odour molecules.
Answer:
a
Explanation:
what is the best explanation for how we can exhibit so many different traits from so few genes
Answer:
Alleles of a gene are responsible for different traits
Explanation:
There are several variant of a gene which in pair leads to varied phenotypic characteristics or traits.
For instance, there are three alleles for blood group i.e A, B and O but there are in totality there are basic 8 blood groups including the categorization on the basis of Rh factor.
Likewise, there are several variations of skin color; however there are majorly six genes that are responsible for skin color.
So, basically alleles of a gene are responsible for different traits
Cell division by mitosis is a mechanism of asexual cell replication. Some single-cell organisms reproduce by cell division, and cell division enables multicellular organisms to grow and to repair damaged cells. Which of the following are products of cell division by mitosis?
A. two daughter cells with identical chromosomes
B. daughter cells with half the number of chromosomes
C. daughter cells that are genetically variable
D. four daughter cells that are genetically the same
Answer:
The correct answer is A. two daughter cells with identical chromosomes
Explanation:
Mitosis is also known as equation division because in mitosis one cell divide into two daughter cells having identical chromosomes. In higher eukaryotes, mitosis helps in the growth of the organisms by increasing cell number. It also helps in replacing the damaged and old cells in multi-cellular organisms.
Some single-cell organisms use mitosis to reproduce. In mitosis first, the genetic material and other organelles get double and then the cell gets separated into two daughter cells having identical genetic material and other organelles. So in mitosis genetically identical cells are produced. So the right answer is A.
Ocean sediments consist of particles that have slowly settled out of the water by which of the following the processes:
Answer:
E) Suspension settling
Explanation:
Ocean sediments consist of particles that have slowly settled out of the water by which of the following the processes?
A) Paleooceanography
B) Grain lithification
C) Porosity reduction
D) Sediment compaction
E) Suspension settling
Suspension settling is the process by which the particulates present in the liquid settle down at the bottom and form a sediment. The particles tend to settle down at the bottom owing to the force of gravity and due to the centrifugal motion.Thus, the particles that are present in the ocean also settle down in the same manner at the bottom of the ocean to form ocean sediments and thus process is also known as suspension settling.Ocean sediments accumulate through a process known as sedimentation. The sediments contain a mix of organic matter, minerals, and small rock particles that have settled out of the water column over time
Explanation:Ocean sediments accumulate through a process known as sedimentation. This involves particles gradually settling out of the water column over time. The sediments typically consist of a mix of organic matter, minerals, and small rock particles. These particles can originate from various sources such as the weathering and erosion of land rocks, marine organisms' remains (organic matter), and atmospheric dusts. The sinking speed of these particles can depend on their size, shape and density. Larger or denser particles generally sink faster than smaller or lighter ones. This gradual depositing process forms layers of sediments over time on the ocean floor.
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A species of malaria-carrying mosquito lives in a forest in which two species of monkey, A and B, coexist. Species A is resistant to malaria, but species B is not. The malaria-carrying mosquito is the chief food for a type of bird in the forest. If all these birds were suddenly eliminated by hunters, which of the following would be an immediate observable consequence?
Answer:
(B) increased mortality in monkey species B
Explanation:
The following deduction can be made from the question:
Species B is susceptible to malariaThe more the population of malaria-carrying mosquito, the more the incidence of malaria in the population of species BA species of bird has been limiting the population of malaria-carrying mosquito by feeding on them. Consequently, this bird species has been indirectly reducing the incidence of malaria in species BHence, if all the birds were suddenly eliminated by hunters,
Malaria-carrying mosquito population will thrive in the forest,Incidence of malaria will increase in species BThis will consequently lead to increased mortality in monkey species BThe correct option is B.
You are interested in researching the effects of vitamin C on colds. For your study, you round up a group of people, all roughly the same age and healthy. You give them all vitamin C pills to take every day and have them check in with you once a month to see if they get a cold. Why is this not a good study design
Answer: the research study lacked a control group, It was difficult to know individuals who are not taking Vitamin C and exposed to cold
Explanation:
Normally in a research study there should be a control group of the same age group like the study group in the same environment, who will not Vit, C but a placebo. To determine if Vitamin. C is the actual effective drug for prevention of cold in the study group or other factors.
Therefore, in this study It was difficult to know individuals who were not taking Vitamin C and exposed to cold(control group) Because, it is the comparison of the data from the control group and the study groups that is needed to determine the efficacy of Vitamin C
The study of minerals is called mineralogy. There are different types of minerals are there and these are calcium, phosphorus, magnesium, sodium and etc.
The correct answer is the research study lacked a control group, It was difficult to know individuals who are not taking Vitamin C and exposed to cold
What are minerals?A mineral or mineral species is, broadly speaking, a solid chemical compound with fairly well-defined chemical composition and a specific crystal structure that occurs naturally in pure form. The geological definition of mineral normally excludes compounds that occur only in living beingsNormally in a research study, there should be a control group of the same age group like the study group in the same environment, who will not have Vitamin, C but a placebo. To determine if Vitamin. C is the actual effective drug for the prevention of cold in the study group or other factors.
Therefore, in this study, It was difficult to know individuals who were not taking Vitamin C and were exposed to cold(control group) Because it is the comparison of the data from the control group and the study groups that are needed to determine the efficacy of Vitamin C.
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How does a multicellular organism develop? One cell grows bigger. The cells shrink. The cells differentiate. The cells replicate to form exact copies.
Answer: The cells differentiate.
Explanation:
In biology, differentiation refers to the gradual formation of organs or parts by a process of evolution or development, as when the seed develops the root and the stem, the initial stem develops the leaf, branches, and flower buds;
OR
in animal life, when the germ cell evolves the digestive and other organs and members, or when the animals as they advance in organization acquire special organs for specific purposes.
Note that option A and D explains organism growth NOT development
Multicellular organisms develop from a single cell through cell division and differentiation where cells specialize to perform different functions leading to the growth and functioning of the organism.
Explanation:A multicellular organism develops from a single cell through a process known as cell differentiation. Initially, the single cell replicates itself to form many exact copies. This is a process called cell division, specifically mitosis, where one cell divides to produce two identical cells. As the organism continues to develop, these cells begin to differentiate, meaning they start to specialize and take on different functions within the organism. Cells could become specific tissues such as muscle cells, nerve cells, or any other type of cells depending on the needs of the organism. This process of cell differentiation allows the multicellular organism to grow and function effectively.
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An increase in the amount of carbon dioxide in the blood stimulates the respiratory center of the brain. As a result, impulses are sent from the(1) medulla to the diaphragm, increasing the rate of breathing(2) cerebrum to the chest muscles, decreasing the rate of breathing(3) medulla to the trachea, causing it to constrict(4) cerebrum to the alveoli, causing them to activelytransport oxygen
Answer:1) medulla to the diaphragm, increasing the rate of breathing
Explanation:
Basically involuntary respiration is controlled by the Respiration centers in the brain Stem. They are group of respiratory neurons ; the dorsal and ventral respiratory groups located in the medulla oblongata , and the pontine respiratory group located in the Pons varolii.
The primary function of this center is for creation and maintenance of respiration rhythms and adjustment of the sequences to fluctuation in body homeostatic balance .
In order to regulate respiration rate and its depth, it collects its input signals from chemoreceptors ( cells that generate biological signals from chemical substances), mechanoreceptors( receptors which relay external physical stimuli of touch, and pressure to internal stimulus by regulation of gated ion channels), the hypothalamus and the cerebral cortex. The fluctuation in the levels of plasma C02, oxygen, and blood pH, stimulated the input progression.
Therefore an elevated C02 blood levels, marked by low pH send input signals to the respiratory centers in the medulla.The latter sends signals to the respiratory muscles (and the diaphragm,) to initiate mechanism of rapid breathing to exhaled more C02 so that the acidity of the blood is reduced..
The correct choice is the medulla sending signals to the diaphragm to increase the rate of breathing in response to high levels of carbon dioxide. This process involves deepening respiration to bring CO2 levels back to normal.
Explanation:The major factor that stimulates the respiration centers in the medulla oblongata and pons is the concentration of carbon dioxide (CO2) in the blood. An increase in CO2 prompts the medulla to send impulses to the respiratory muscles. When CO2 levels rise, it diffuses across the blood-brain barrier and results in increased hydrogen ion concentration, which in turn lowers the pH of the blood.
This acid-base effect is sensed by central chemoreceptors, which initiate a response to increase the contraction of the diaphragm and intercostal muscles. Consequently, the rate and depth of respiration increase, and more CO2 is expelled, bringing levels in the blood back to normal.
To answer the student's question directly, the correct choice is: (1) medulla to the diaphragm, increasing the rate of breathing. This process helps regulate the levels of CO2 and maintain a stable pH, ensuring proper function of the body's systems.
Check all that are characteristics of the esophagus. Check All That Apply a) The mucosa is composed of thick, nonkeratinized stratified squamous epithelium.b) The mucosa is composed of thick, nonkeratinized stratified squamous epithelium. c) It is composed entirely of smooth muscle.It is composed entirely of smooth muscle. d) The two layers of muscle in the superior one-third of the muscularis are skeletal. e) The two layers of muscle in the superior one-third of the muscularis are skeletal. f) It is located almost entirely in the abdomen.It is located almost entirely in the abdomen.
Answer:
a) The mucosa is composed of thick, nonkeratinized stratified squamous epithelium.
d) The two layers of muscle in the superior one-third of the muscularis are skeletal
(B and E are repetition of A and D respecticely)
The correct characteristics of the esophagus are:
a) The mucosa is composed of thick, nonkeratinized stratified squamous epithelium.
The mucosa of the esophagus is lined with a thick layer of nonkeratinized stratified squamous epithelium. This type of epithelium provides protection against mechanical and chemical damage.
d) The two layers of muscle in the superior one-third of the muscularis are skeletal.
The muscularis layer of the esophagus is made up of two layers of muscle: an inner circular layer and an outer longitudinal layer. In the superior one-third of the esophagus, the muscle is composed of skeletal muscle fibers, allowing for voluntary control over swallowing.
f) It is located almost entirely in the abdomen.
The esophagus extends from the throat (pharynx) down through the chest and passes through the diaphragm to connect with the stomach in the abdominal cavity. While a small portion of the esophagus is located in the thoracic cavity, the majority of it lies within the abdomen.
Therefore, options a, d, and f are the correct characteristics of the esophagus.
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Which of the following is included in four basic concepts of medical ethics? 1. Beneficence 2. Nonmaleficence 3. Loyalty privileges 4. both A and B
Answer:
Option 4
Explanation:
There basic principles of medical ethics which are as follows –
a) Autonomy- This provides patients the freedom of thought and decision making regarding taking any medicare services. It is the duty of the medical service provider to provide complete details about the service so that the patient can take an informed decision
b) Justice – The medical practice being applied must abide by the existing rules and laws.
c) Beneficence – It cover the efficiency of the care provider to provide skilled and knowledgeable staff who must have received adequate training
d) Non-maleficence – The service provider must ensure that no one is harmed in this procedure.
Hence, option 4 is correct
Beneficence and nonmaleficence are included in four basic concepts of medical ethics.
The correct option is 4; both A and B
What are the basic concepts of medical ethics?The fundamental medical ethics concepts are as follows:
a) Autonomy – This gives patients the ability to choose whether or not to use any Medicare services. In order for the patient to make an informed decision, it is the responsibility of the medical care provider to give comprehensive information about the service.
b) Justice – The medical procedure must follow all applicable laws and regulations.
c) Beneficence - This refers to the efficiency of the care provider in supplying knowledgeable, skilled personnel who must have undergone sufficient training.
d) Non-maleficence - The service provider is responsible for making sure that no one is hurt throughout the process.
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Drosophila melanogaster, the fruit fly, has a 2n chromosome number of 8. Assuming that a somatic G2 nucleus contains about 8.0 picograms of DNA, how many picograms of nuclear DNA would you expect in:
a) Mitotic metaphase
b) a primary oocyte (metaphase)
c) a secondary oocyte (metaphae)
d) a first polar body (metaphase)
Answer:
a) Mitotic metaphase
8 picograms
b) a primary oocyte (metaphase)
8 pecograms
c) a secondary oocyte (metaphae)
4 pecograms
d) a first polar body (metaphase)
4 pecograms
Explanation:
a) In mitotic phase the chromosome numbers remains same as 8 because in this phase duplicated chromosomes align in center and separate to other poles. Therefore the amount of DNA will be 8 pecograms.
b) after the mitotic meta phase the cells divide into daughter cell with equal proportion of DNA which means each cell have 8 chromosomes. therefore they both contain 8 pecograms of DNA. The new daughter cells called as primary oocytes.
c) These primary oocytes (8 chromosomes) divides into two secondary oocyte each contain 4 chromosomes which means each cell have 4 pecograms of DNA.
d) Duplication of chromosomes occur in secondary oocyte and cell divides into polar body (4 chromosomes) and ovum (4 chromosomes). Therefore first polar body have 4 pecograms of DNA in it.
See the attachment for clarification.
During mitotic metaphase and primary oocyte metaphase in Drosophila, there are 8.0 picograms of DNA. In a secondary oocyte during metaphase and the first polar body, there are 4.0 picograms of DNA, as these cells are haploid postcompletion of meiosis I.
Explanation:In the context of Drosophila melanogaster, which has a diploid chromosome number of 8 (2n=8), and a somatic G2 nucleus containing about 8.0 picograms of DNA, we can determine the amount of DNA present at different stages of cell division. During the G2 phase, a cell has duplicated its DNA in preparation for mitosis, therefore, a G2 nucleus contains twice the amount of DNA compared to a G1 nucleus.
(a) Mitotic metaphase: In mitotic metaphase, the cell contains 2 copies of each chromosome, just as it does during G2 phase, so you would expect to see 8.0 picograms of DNA, because the chromosomes are aligned and condensed but not yet separated.(b) Primary oocyte (metaphase): A primary oocyte in metaphase I of meiosis also contains 8.0 picograms as it is still diploid until the completion of meiosis I.(c) Secondary oocyte (metaphase): After the completion of meiosis I, a secondary oocyte is in meiosis II, and is already haploid, but since the chromosomes have not yet divided, it would contain 4.0 picograms of DNA, half of the amount in the primary oocyte before meiotic division.(d) First polar body (metaphase): The first polar body, being a byproduct of meiosis I, would similarly contain 4.0 picograms of DNA.
A swine producer wants to know if the average weight of his pigs is different from the breed average of 230 lb. He selects a random sample of 16 weights from pigs in his herd and calculates a sample mean of 220 lb and a sample standard deviation of 25 lb. Assume that he wants to detect departure from 230 lb in either direction and that he uses a significance level of 0.10. Calculate the value of the test statistic needed to test the null hypothesis.
Answer: t= -1.60
Explanation:
Let [tex]\mu[/tex] be the population mean weight of pigs.
As per given , we have
[tex]H_0:\mu=230[/tex]
[tex]H_0:\mu\neq230[/tex]
Sample size : n= 16
Sample mean =[tex]\overline{x}=220\ lb[/tex]
Sample standard deviation : [tex]s=25\ lb[/tex]
Since the population standard deviation is not known so the test is a t-test.
Test statistic for population mean : [tex]t=\dfrac{\overline{x}-\mu}{\dfrac{s}{\sqrt{n}}}[/tex]
[tex]t=\dfrac{220-230}{\dfrac{25}{\sqrt{16}}}[/tex] (Substitute all the values.)
[tex]t=\dfrac{-10}{\dfrac{25}{4}}[/tex]
[tex]t=\dfrac{-40}{25}=-1.60[/tex]
Hence, the value of the test statistic needed to test the null hypothesis : t= -1.60
What is the name of the process whereby a platform with many wells is secured to the ocean floor?
A. offshore drilling
B. secondary recovery
C. underground mining
D. geothermal extraction
Answer:
Option A, Offshore Drilling
Explanation:
In the process of offshore drilling, oil is extracted from the wells which are located at the surface of ocean floor.
Different types of oil rigs are used for oil extraction depending on the depth of the ocean.
It is a good mode of extracting oil from sources that have remained untapped since long. With the new technology, several nations have been able to explore this oil reserve and have become independent in terms of energy
Hence, option A is correct
A. offshore drilling
-----------------------------------
A researcher uses a radioactively-labeled carbon dioxide molecule to evaluate photosynthetic rate. In her experiments, the researcher finds adequate consumption of water, generation of oxygen and NADPH production, but no change in plant mass. The most likely dysfunctional system in the plant is:_______________________________.
Answer:
Answer is Calvin cycle.
Explanation:
Calvin cycle is very important to plants because it helps in the conversion of organic products for the usefulness of plants. This is because the carbon dioxide and water are converted to glucose, which is useful to plants.
Calvin cycle can be explained as the production of glucose through the use of chemical energy from NADPH and ATP, produced in light reactions, to convert the atmospheric carbon dioxide to RuBP, which is a five-carbon molecule.
During which of the phases of growth, does the number of new cells balance the number of declining cells?
Answer:
The correct answer is stationary phase.
Explanation:
There are four phases in a growth curve lag, log, stationary, and death phase. During the lag phase, cells adapt to the new environment and no growth occurs. During the exponential phase, cells grow at an exponential rate.
The stationary phase is the phase where the number of cells remains constant because the number of production of new cell becomes equal to the number of cell death. This phase shows that the culture reached its carrying capacity.
During the death phase, the number of cells starts declining because of the declining resources. Therefore the correct answer is the stationary phase.
A certain cell type has existed in the blood and tissue of its vertebrate host's immune system for over twenty years. One day, it recognizes a newly arrived antigen and binds to it, subsequently triggering a secondary immune response in the body. Which of the following cell types most accurately describes this cell?
Answer:
The options are
A) thyroid cells
B) macrophage
C) memory cell
D) plasma cell
C) memory cell is the ANSWER
Explanation:
B lymphocytes is one of the important cells of the immune system. It's the building block for the memory cells which acts as a means of recognizing pathogens that have previously infected the body system in order to boost the production of antibodies against such pathogen for faster immune response in future infections
On genetic analysis, a human liver cell (hepatocyte) is found to be 46XX, with each chromosome composed of two chromatids. Microscopic examination of the cell reveals an intact nuclear membrane and no chromatin can be seen. It must be true that this cell is:____________.
Answer:
The options
A.) in the G₂ stage of the cycle.
B.) in the M stage of the cell cycle.
C.) about to under meiosis I.
D.) is evidence of hepatocellular carcinoma.
The ANSWER IS SURELY A
A.) in the G₂ stage of the cycle.
Explanation:
The Answer is A
Which indicates the interphase composed of G₁, S, and G₂ for the cell 46XX, with two chromatids on each chromosome to imply that synthesis has taken place.
Since the cells has intact nuclear membrane with no chromatin visible, the cell is at the S or G₂ phase
Answer B is wrong.
Reason:
For the cell to be at M phase then there must be dissolution of the nuclear membrane and chromatin becomes evident or seen at various stages such as within the nucleus, at the equatorial plane and the opposite poles of the cells
Answer C is wrong
Reason:
since the cell does not undergo meiosis. Therefore, it is a hepatocyte and not a sex cell that can undergo meiosis
You learn that a Mars lander has retrieved a bacterial sample from the polar ice caps. You obtain a sample of this bacteria and perform the same kind of experiment that Meselson and Stahl did to determine how the Mars bacteria replicates its DNA. Based on the following equilibrium centrifugation results, what type of replication would you propose for this new bacteria?
Answer:
The list of options to complete the question are
a. conservative replication
b. semi conservative replication.
c. dispersive replication
d. discontinuous replication
e. continuous replication
THE ANSWER IS C.
c. dispersive replication
Explanation:
In this type of DNA replication, the original DNA chain is broken down and combined randomly before the
unwinding of the double helix structure and separation to form a template for synthesis of messenger RNA
Scientists use various types of models to represent real world activity. For instance, computer models are used to predict weather patterns, and the physical models of Thomson and Rutherford have been used to help us understand the structure of the atom.Scientific models like this are useful because they can help to describe and predict natural behavior. However, such models are limited, andA. they in no way reflect the natural worldB. their predictions are almost never accurateC. their predictions are not accurate every single timeD. they can only be used by experienced scientists to make relevant predictions
Answer:
(B.) their predictions are almost never accurate
Explanation:
A model is a representation of an idea, process that scientists use in explaining a complex data to a more simple and understable way. Models reflect the natural world e.g. climate models are used by humans to learn and to know about carbon cycles, water cycles and the weather. Model do come with some limitations one of them is an incomplete detail e.g. measuring the distance round the earth, we were made to believe that the model of the Earth is spherical, so in calculating the distance round the earth certain details are missing like the variations in distance caused by valleys and mountains and other topological problems that might be encountered.
Answer:
C
Explanation:
C is the CORRECT answer... Not B. I just took this test and the answer was "Their predictions are not accurate every single time."
Which physical change always happens to both the male and female body during puberty?
A. muscle development
B. increase in perspiration
C. increase in body fat
D. formation of eggs
B
Increase in perspiration is a physical change that happens to both the male and female body during puberty.
Explanation:
An increase in sweating during puberty is as a result of increased activity of the glands due to rapid hormonal changes in the body during this time. There is an increased testosterone levels in boys while estrogen increases in girls. Other common signs in boys and girls during puberty is the growth of pubic and armpit hairs.
The evident differences in puberty growth include that girls will have their hips and breasts become larger, while boys will have enlargened shoulders and muscles.
Learn More:
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Dr. Frankenstein has forgotten to give his monster an important part; as a result, the monster cannot transduce sound. Dr. Frankenstein has omitted the __________.A. eardrum.
B. middle ear.
C. semicircular canals.
D. basilar membrane.
Answer: A
Explanation:
sound vibration are tranduced by hair cells to the inner ear (electrical energy). sound vibration from an object causes vibration to air molecules which in turn vibrates to the ear drum.
The correct answer is B. Dr. Frankenstein has forgotten to give his monster an important part as a result, the monster cannot transduce sound. Dr. Frankenstein has omitted the middle ear.
The middle ear is the part of the ear that transduces sound from the air to the fluid-filled inner ear. It consists of the eardrum and the ossicles, which are the tiny bones that amplify and transmit the vibrations from the eardrum to the oval window of the cochlea. Without a middle ear, the monster would not be able to transduce airborne sound waves into mechanical vibrations that can be processed by the inner ear. Here's the reasoning behind the elimination of the other options: A. Eardrum - The eardrum, also known as the tympanic membrane, is part of the middle ear and is involved in the transduction of sound. However, the eardrum alone is not sufficient for sound transduction; the middle ear as a whole, including the ossicles, is necessary. C. Semicircular canals - The semicircular canals are part of the vestibular system in the inner ear, which is responsible for balance and spatial orientation, not for hearing or sound transduction. D. Basilar membrane - The basilar membrane is located in the cochlea of the inner ear and is involved in the transduction of sound from mechanical vibrations to neural signals. However, for the basilar membrane to be involved, the sound must first be transmitted through the middle ear.
In general, operons that encode the enzymes of a biosynthetic (anabolic) pathway (such as the trp operon) are _____, and those encoding the enzymes of a catabolic pathway (such as the lac operon) are ___.
a.repressible; inducible
b.inducible; repressible
c.permanently on ; permanently off
d.permanently off; permanently on
e.easily mutated; resistant to mutations
Operons associated with biosynthetic pathways, like the trp operon, are repressible, while those related to catabolic pathways, like the lac operon, are inducible. The correct answer is a. repressible; inducible.
In general, operons that encode the enzymes of a biosynthetic (anabolic) pathway (such as the trp operon) are repressible, and those encoding the enzymes of a catabolic pathway (such as the lac operon) are inducible. Therefore, the correct answer is a. repressible; inducible.
Repressible operons, like the trp operon, typically contain genes encoding enzymes for biosynthetic pathways and are turned off in response to the presence of the end product of the pathway, like tryptophan. Meanwhile, inducible operons, such as the lac operon, often contain genes that are necessary for the metabolism of a specific substrate such as lactose and are turned on only when that substrate is present in the environment.