Answer:
True
Explanation:
In phase-contrast objective and a phase contrast optical systems is equipped with Light microscope .
Phase contrast microscope is used to differentiate unstained structures in a cell that differ in refractive indices and thickness. Thus it is usefull for examining living unstained organisms.
Light that passed through materials of different refractive index and/or thickness will undergo a change in Phase. The difference in phase or wave front irregularities cause variation in brightness of the structures.
Hoping this might help!!!
The statement about phase-contrast microscopy utilizing differences in refractive indices for better viewing of living specimens is true. It provides enhanced contrast by amplifying phase differences due to refractive index variations without staining the specimens.
The statement that in phase-contrast microscopy, the differences in refractive indices between organisms and their environments are utilized for better viewing of living specimens is True. The principle of the phase-contrast microscope harks back to the idea of refractive index. It details that cells have a different refractive index than their surroundings, which affects the phase of the light transmitted through them. This difference is subsequently amplified by a phase ring in a special phase objective, allowing the phase differences to be translated into differences in brightness, and thereby enhancing contrast without the need to stain the specimen.
This technology leverages wave interference and differences in phases, resulting in a dark image of the object amidst a bright background. Because of this, it becomes a most cost-effective tool for examining live, unfixed, and unstained specimens such as eukaryotic cells, showcasing organelles, and prokaryotic cells, visualizing endospores.
the nurse completes dietary teaching with a client who has chronic kidney failure. the nurse determines more teaching is needed when the client makes which statement?
Answer:
The options
"I will eat more oranges and other foods with vitamin C."
"I should increase dairy products in my diet."
"I should add protein powder to my fruit smoothies."
The CORRECT ANSWER IS
"I will eat more oranges and other foods with vitamin C."
Explanation:
"I will eat more oranges and other foods with vitamin C."
Citrus fruits are rich in potassium and should be stayed away from, since kidneys find it difficult to remove the excess potassium. Examples of foods that are rich in potassium are dried fruits, avocado, tomato, potatoes, and bananas. This statement indicates that additional teaching is needed.
In kidney failure, the client stands a higer chance for hyperkalemia, hypernatremia, and hyperphosphatemia.
Potassium, is found in large amounts in citrus fruits and dried fruits, and there's need to take these fruits with caution.
Phosphorus is limited due to the important balance of potassium electrolyte with calcium. Protein is inhibited as the failure to remove uric acid, which is produced during protein metabolism, via the kidneys. Sodium, obtained in foods, is also restrained to avoid fluid overload and edema.
Illness characterized by headache, nausea, vomiting, dyspnea, and insomnia. It typically begins 6 to 96 h after one reaches high altitude and lasts several days.
Answer: Acute Mountain Sickness or Altitude sickness.
Explanation:
Acute Mountain sickness results from the inability to adjust to the lowered oxygen pressure of high altitudes. The best thing to do when experiencing symptoms is to descend to lower altitudes and receive oxygen.
Which biome has no large trees because much of the soil is frozen? A. chaparral B. desert C. savanna D. tundra
Answer:
c
Explanation:
Answer:
D. Tundra
Explanation:
When dark-colored fur gives mice a 1% competitive advantage and 1% of the population begins with dark fur, in about 1,000 years, 95% of the population will have dark fur. Which of the following statements is true?
A. Dark-colored rock pocket mice, in this population, have fewer offspring than light-colored rock pocket mice.
B. If dark-colored rock pocket mice had a competitive advantage of 0.1%, it would take more than 1,000 years for 95% of the population to have dark fur.
C. If dark-colored mice had a competitive advantage of 5%, it would take more than 1,000 years for 95% of the population to have black fur.
D. If dark-colored mice had a competitive advantage of 10%, it would take more than 1,000 years for 95% of the population to have black fur
Answer:
"If dark-colored rock pocket mice had a competitive advantage of 0.1%, it would take longer for 95% of the population to have dark fur." the statement is true
Explanation:
The greater effect of the crossing over is basically to spread the variation through the population. This is the basic difference even between sexual and non sexual mode of reproduction.The offspring produced might get get more variety when compared to the parent. From this the genetic recombination happens. This also often lead to the intrachromosomal mixing that takes place between the alleles and the homologous pair. This is the exchange of the chromosome segments among the non sister chromatids in meiosis.
If a dark-colored mouse has a competitive advantage of 0.1%, it would take more than 1,000 years for 95% of the population to have dark fur due to the process of natural selection.
Explanation:The correct statement related to the effect of a competitive advantage on the prevalence of dark-colored fur in a mouse population is statement B: If dark-colored rock pocket mice had a competitive advantage of 0.1%, it would take more than 1,000 years for 95% of the population to have dark fur. This is a question of natural selection, where a trait that confers a competitive advantage (in this case, dark-colored fur) spreads through a population over generations. The bigger the competitive advantage, the faster the trait spreads. For example, with a 1% advantage, it takes around 1,000 years for the population to predominantly acquire the trait. Therefore, it stands to reason that if the advantage were reduced to 0.1%, the spreading process would take correspondingly longer.
Learn more about Natural Selection here:https://brainly.com/question/32227158
#SPJ3
The removal of a keystone species from a community usually results in:________ a. the death of all other community members. b. the disappearance of that community. c. substantial changes in the abundance of many species. d. minor changes, if any.
Answer: Option B (disappearance of that community)
Explanation:
Keynotes species are species of organisms that greatly affect the structure of its environment.
Keynotes species plays great role in ensuring the structure, checkmating the abundance and diversity of other species of an ecosystem.
In absence of keystone species, the ecosystem will be overpopulated above the carrying capacity (i.e the resources available for organisms in their ecosystem) will definitely leads to competition, disease outbreak, malnutrition etc.)
However, when the important primary producers of the ecosystem (Plants species) are wiped out due to overfeeding caused by abundance of herbivores that supposed to be checkmated by the keystone species. Hence, the extinction of plants will cause the extinction of other organisms in that community. Thus, the community will cease to exist.
The removal of a keystone species typically causes substantial changes in the abundance of many species within their ecosystem, by disrupting the balanced community structure and possibly leading to an extinction cascade; hence option c is correct
The removal of a keystone species from a community usually results in substantial changes in the abundance of many species. Keystone species play a disproportionately significant role relative to their abundance in maintaining the structure and health of their ecosystems. Examples include sea stars in coral reef communities, which, by preying on species such as mussels and sea urchins, prevent any single species from dominating and promote greater biodiversity. Similarly, the banded tetra provides essential nutrients to its ecosystem, and its loss can drastically alter community structure. The loss of such species can lead to an extinction cascade, severely affecting ecosystem composition and functioning.
Turbidity is a term used to describe water clarity, or how clear water is. Cloudy water is said to be turbid. Turbid water may be a result of a buildup of sediments, which are pieces of rocks that have been broken down and eroded or transported by surface runoff. Human activities that remove plants in an area may increase erosion.
Sediments can get into the gills of fish, which can then decrease their growth and delay development. Sediments prevent sunlight from reaching the producers of the aquatic ecosystem, such as algae. This in turn affects the food webs in this ecosystem.
Which human activities would most likely increase turbidity? Check all that apply.
cutting down trees
building roads in mountains
constructing buildings
planting gardens in vacant lots
removing sediments from sidewalks using water
Cutting down trees, building roads in mountains, constructing buildings and removing sediments from sidewalks using water does donate to increase the turbidity of water.
Explanation:Turbidity of water is formed due to a suspension formation of water and the dust and dirt along with several insoluble particles. This turbidity is actually formed in nature due to erosion by water or wind which gets deposited in water. Removing trees or construction of road leads to loosening of ground soil which is easily washed away by water. Construction of buildings also results in cutting of trees. The washing of sediments with water also increases the chance of turbidity of water.
Answer:
A,B,C,E
Explanation:
I did it myself. Have a great day/night. <3
Organisms with a circulating body fluid that is distinct from the fluid that directly surrounds the body's cells are likely to have _____.
Answer:
The correct answer is- a closed circulatory system.
Explanation:
There are two types of circulatory system, open circulatory system and closed circulatory system. In an open circulatory system, the blood flows through cavities and no blood vessels are present here from which blood can flow. Open circulatory system is found in invertebrates.
In organisms which have closed circulatory system, blood vessels are present in which blood flows and reaches to different cells in the body.
So in organisms that have closed circulatory system blood or body fluid does not directly surround the body cells as in the open circulatory system. So the right answer is-a closed circulatory system.
Final answer:
Organisms with distinct body and cell-surrounding fluids have a closed circulatory system, separating blood from interstitial fluid, unlike open systems where hemolymph mixes with interstitial fluid.
Explanation:
Organisms with a circulating body fluid that is distinct from the fluid that directly surrounds the body's cells are likely to have a closed circulatory system. In a closed circulatory system, the heart pumps blood through vessels that are separate from the interstitial fluid of the body. This is in contrast to an open circulatory system where a fluid called hemolymph is pumped into the body cavity and is mixed with the interstitial fluid. The earthworm, for instance, has a closed circulatory system, as do most vertebrates and some invertebrates.
What does "adaptation" mean in an evolutionary context?
a. the ability of organisms to alter their appearance under changing environmental conditions
b. the accumulation of favorable variations in a population over time
c. the way an individual's body adjusts to its environment
d. all of the answers are correct
In an evolutionary context, adaptation refers to the accumulation of favorable variations in a population over time. These changes happen at a genetic level, allowing organisms to compete for resources effectively. An example of such adaptation is the development of longer necks in giraffes to reach higher leaves.
Explanation:In an evolutionary context, adaptation refers to b. the accumulation of favorable variations in a population over time. It involves changes in organisms at a genetic level over generations. Adaptations occur in response to changes in the environment that allow organisms to remain competitive for survival resources. These favorable traits become more common in the population over time.
An example might be the development of longer necks in giraffes, an adaptation that enabled them to reach higher leaves for sustenance and thus survive when low-lying food sources were scarce. Thus in essence, adaptation can be seen as nature's way of ensuring survival of a species in varying environmental conditions.
Learn more about Adaptation here:https://brainly.com/question/31886336
#SPJ2
What is the strong tendency to believe that one's own culture is normal, natural, and superior to other cultures called
Answer: Ethnocentrism
Explanation:
Ethnocentrism refers to the tendency to see other people's culture i.e way of life such as mode of dressing, eating pattern, marital rites etc as INFERIOR, while ONLY your own culture is normal, natural and superior, and should therefore be adopted by all people.
Answer:
Ethnocentrism.
Explanation:
Ethnocentrism may be defined to explain the individual's behavior and thinking on the basis of culture. The ethnocentrism term was first used by William G. Sumner.
The ethnocentrism explain the strong association of the one's belief and its influence by the culture. The ethnocentrism create the feeling of the superiority of the culture and shows the judgmental behavior on the different culture.
Thus, the answer is ethnocentrism.
In an experiment with an enzyme, the 58th amino acid seems to form a covalent bond with a substrate molecule as part of the catalytic process. What would you say?
Answer:
At some point the bond between the amino acid and the substrate must break.
Explanation:
Enzymes are the biocatalyst that can increase the speed of the biochemical reactions of the living organisms. All enzymes are made of proteins except ribozymes.
During the catalytic process, the enzymes can form covalent modification. This is only possible when the bonds between the substrate and amino acid is broken. This breaking and formation of bond is important so that enzyme can makes the substrate free and the steps can be repeated again.
The class of disorders marked by extreme and inflexible characteristics that often cause impaired social and occupational functioning are referred to as _____ disorders.
Answer:
Personality.
Explanation:
The mental disorders affects the thinking ability of the individual. The mental disorder individual shows abnormal behavior in the society and might feel anxiety or feel awkward among the people.
The personality disorder is a type of the mental disorder in which the individual have unhealthy thinking level. This disorder affects the social status and his personality in the society. The occupational functioning become improper and requires the proper medical treatment.
Thus, the answer is personality.
Researchers hypothesized that cocaine is pharmacologically active in primate fetal brain when pregnant primates are administered cocaine at doses typically used by human drug users. What experimental observation best supports this hypothesis?
A. Glucose metabolism in the fetal brain increased
B. Imaging studies showed that cocaine entered the fetal circulation
C. The fetus had an increase in tolerance to pain
D. Imaging studies showed internalization of dopamine receptors
Answer:
Option A, Glucose metabolism in the fetal brain increased
Explanation:
Usage of cocaine during pregnancy is prohibited. However, in case if cocaine is taken it disrupts the metabolism as it increases brain glucose metabolism to the level of an adult human being. Since glucose metabolism in brain is a sensitive process, any disruption in it can lead to unaccounted effects such as dysfunctional circulation, and pharmacological effect. Cocaine increases the dopamine by blocking the dopamine transporters thereby increasing the Vmax. Since the brain of a child has all kind of neurochemical components, cocaine intakes by a pregnant woman produces reinforcing effects in brain of fetus and also make it pharmacologically active
Hence, option A is correct
An insured has endured multiple surgeries and hospitalizations for an illness during the summer months. Her insurer no longer bills her for medical expenses. What term best describes the condition she has met?
Answer:
Stop loss limit.
Explanation:
The health insurance may be defined as a type of agency or policy that covers the medical expenses of the individual either fully or completely. The individual must pay some amount for the continuity of the health insurance.
The stop loss limit in a health insurance determines that the insurer do not pay for the medical expenses of an individual. This might occur when the insurance amount has been reached up to a certain limit and this limits the insurer loss.
Thus, the answer is stop loss limit.
In the third stage of birth, the placenta, umbilical cord, and other membranes are expelled from the uterus. This stage of birth is called the _________
Answer:
The "Afterbirth" stage.
Explanation:
The third stage of birth, where the placenta, umbilical cord, and other membranes are expelled, is called the afterbirth. It follows the expulsion of the baby and concludes the childbirth process.
In the third stage of birth, the placenta, umbilical cord, and other membranes are expelled from the uterus. This stage of birth is called the afterbirth. It follows the second stage of labor, where contractions are very strong and, with the mother's effort, expel the baby from the uterus.
During the afterbirth phase, the placenta, amniotic sac, and the remnants of the umbilical cord, which were vital for providing nutrients and oxygen to the baby while in the uterus, are delivered. This usually happens within a few minutes after the baby is born. The completion of the third stage marks the end of the childbirth process.
A boy has blood type MN with a genotype of LMLN. His red blood cells possess both the M antigen and the N antigen. What is the relationship between his two alleles for this gene?
Answer:
Co-dominance
Explanation:
Co-dominance is a genetic phenomenon where two versions of a gene called alleles are neither recessive nor dominant to one another. Hence, the phenotypic expressions encoded by both alleles are expressed simultaneously.
In this case of the MN blood system, the boy has a LMLN genotype and expresses both genes M and N in his red blood cells. Hence, alleles M and N are said to be codominant to one another i.e. M is not dominant or recessive to N and vice versa.
The English anesthesiologist who linked cholera outbreaks to contaminated water and innovated several of the key epidemiologic methods that remain valid and in use today was _________.
At what point do you feel it is necessary for environmentalists to get involved in creating man-made problems with natural ecological succession?
Answer: Ecosystem degradation
Definition of terminologies:
1. Natural ecological succession is the gradual change in the species composition and diversity in the ecosystem and the development of ecosystem over a period of time, resulting to stable community.
2. Ecosystem refers to group of plants, animals and other living components functioning in their non-living environment.
3. Ecosystem degradation refers to the depletion of resources in the ecosystem
Explanation:
When there is ecosystem degradation, it is necessary for environmentalists to get involved in creating man-made problems with natural ecological succession and this process is called ecological restoration.
Environmentalists creates man-made problems to either accelerate or reverse the change in the ecosystem.
Degradation comes in different ways (e.g increased soil erosion/flooding, disease outbreak,deforestation, pollution of the ecosystem etc.) and are greatly influenced by climate change.
Environmentalists curb the menace by:
1. Introducing resistant species against disease outbreak;
2. Improved ecosystem service;
3. Buffer zone establishment to resist pollution in any form.
A scientist wishes to determine the effect of a digestive enzyme on starch digestion (starch is broken down into glucose). The experimental setup is to mix the enzyme with starch in a test tube, stop the reaction after a known period of time, and then measure the amount of glucose produced.
Which of the following is the correct experimental control?
Answer:
An identical setup but replacing the enzyme with an equal volume of water
Explanation:
When carrying out any experiment, it is important to set out a control in order to increase the reliability of the data and results.
The control minimizes the effects of variables other than the independent variable.
In the above experiment, starch has to be eliminated and replaced with water. Water does not have starch hence the digestive enzyme being tested will not have any effects making the data and results from the experimental group reliable.
True or false? The absence of a trait cannot be used as a synapomorphy in phylogenetic analysis, only shared derived traits that are present in the clade can be used.
Answer:
This statement is False.
Explanation:
A shared apo-morphy which differentiate a clade from other organisms is called synapomorphy. In simple words, members of monophyletic group shares an apomorphy which indicate the presence or absence of certain organs from clade.
For example, loss of legs in snakes is an important synapomorphy.
Final answer:
The statement is false. In phylogenetic analysis, synapomorphies can include both the presence and the absence of derived traits that are shared by members of a clade, such as the loss of limbs in snakes or the presence of amniotic eggs in certain terrestrial vertebrates.
Explanation:
The statement that the absence of a trait cannot be used as a synapomorphy in phylogenetic analysis is false. A synapomorphy can be either the presence or the absence of a derived trait, as long as it is shared among members of a clade and distinguishes that clade from others. For example, the loss of limbs is a synapomorphy that unites snakes. In cladistics, both shared derived traits (such as feathers in birds, known as apomorphic) and the absence of certain traits can indicate evolutionary relationships. However, it is the derived traits that are critical for constructing phylogenies—whether those traits represent the appearance of new features or the loss of ancestral ones.
Ancestral traits (referred to as plesiomorphic), shared by multiple species, are not useful in determining the relationships within a clade since they do not reveal specific evolutionary paths. It is the derived characters that have changed over time and are shared by a group that are important for cladistic analysis, termed synapomorphies. For instance, the presence of an amniotic egg in lizards, rabbits, and humans is a shared derived character that connects these groups more closely than any of them to fish, lampreys, and lancelets.
The concept of __________ means that because of their genetic makeup, individuals differ in their responsiveness to qualities of the environment.
Answer: Behavioral genetics
Explanation: This concept indicates that our genes influence our environment and in return, the environment influences our genes. Behavioural genetics has therefore expressed gene-environment interactions on the behaviour of an individual.
The concept of the range of reaction means that because of their genetic makeup, individuals differ in their responsiveness to qualities of the environment.
Range of reaction is a concept that explains how genetic and environmental factors interact to shape an individual's development. According to this concept, our genes set the boundaries or limits within which we can develop and perform, while the environment determines where within those boundaries we will fall. This means that even though two people might have similar genetic potentials, their actual abilities and behaviors can differ based on their environmental experiences.
For example, if a person has a genetic predisposition for high intellectual potential but is raised in an environment that lacks educational resources or stimulation, they might not reach their full cognitive potential. Conversely, if the same person is raised in a rich and stimulating environment, they are more likely to achieve their highest potential.
An be inferred from the passage that:_________ a. in an extinction event, there is a dramatic decrease in microbial life on earth. b. over 90% of easily observed, biologically complex species become extinct during a biotic crisis. c. the background extinction rate of animal and plant species is well below 50%. d. marine fossils are easier to find and thus more useful to those studying mass extinction events.
Answer:
C. the background extinction rate of animal and plant species is well below 50%.
Explanation:The Reading Comprehension themed ”An extinction event (also known as a mass extinction or biotic crisis)” was the reference source for the answer.
Option C is correct, it requires that one joins two pieces of information. The start of the 3rd paragraph we see that “the five major mass extinctions have significantly exceeded the background extinction rate” and we later saw that ”the rate of those mass extinctions is over 50%.” This brings one to submit that the background rate of extinction is altogether, below 50%.
A __________ is a currently valued style of behavior, thinking, or appearance that is longer lasting and more widespread than a fad.
Answer:fashion
Explanation:
Assume that in a series of experiments, plants with round seeds were crossed with plants with wrinkled seeds and the following offspring were obtained: 220 round and 180 wrinkled. (6 points total, 2 points each) (a) What is the most probable genotype of each parent? (b) What genotypic and phenotypic ratios are expected? (c) Based on the information provided in part (b), what are the expected numbers of progeny (400 total) of each phenotypic class?
Answer:
a) Rr and rr
b) Phenotypic ratio: 1/2 round, 1/2 wrinkled, Genotypic ratio: 1 (Rr) : 1 (rr)
c) 200 round, 200 wrinkled
Explanation:
Mendel performed experiments where he considered the genes coding for seed shape in them. The allele for round shape (R) is dominant over the allele for wrinkled shape (r). For question a, the parent exhibiting the dominant trait can either be homozygous (RR) or heterozygous (Rr). Since it was crossed with a parent with recessive trait (wrinkled seed shape), it will produce only offsprings with round seed shape if it is in a homozygous state(RR).
But some of the offsprings possessed wrinkled shape (recessive trait), hence, the probable genotype is heterozygous (Rr).
Question b: Based on the probable genotype of the parents in (a) above i.e. Rr and rr, a cross between them will yield offsprings with two phenotypes and genotypes.
The phenotypes will be half (1/2) of round-seeded plants, and half (1/2) of wrinkled seeded plants.
The genotype of the round-seeded offsprings will be Rr while that of the wrinked-seeded offsprings will be rr, in the ratio 2:2 or 1:1.
Question c: Based on the probable phenotypic ratio 1:1 in question b above, out of 400 progenies, 200 will be round-seeded while 200 will be wrinkled-seeded.
Educating the public about the causes of earthquakes and their potential hazards may help to alleviate death and destruction should an earthquake occur, but a country also needs _____ to help prepare for the likelihood of such an event
Answer:
Funds.
Explanation:
Natural disaster may be defined as any harmful event that might occur due to the natural phenomena. The natural disaster might include flood, earthquake, cyclone and volcanoes.
These natural disaster affects the living life as well the public properties. The countries might suffer from the huge financial loss due to these natural disaster. This the duty of the government and the individual to prepare themselves in the disaster and the country must provide funds for the preparation of these disaster.
Thus, the answer is funds.
When conducting an experiment, it is generally necessary to include __________ groups that are treated exactly the same as treatment groups except for the condition being tested.A. ControlB. VariableC. A maximum of fiveD. Experimental
Answer:
A. Control
Explanation:
In any scientific experiment, there are usually two groups under study that are similar to each other except that one receives a treatment or is being manipulated while the other is not. We have the treatment groups and the control groups.
The treatment group is the group that receives a treatment or condition that is being manipulated, while the control group is the group that does not receive the treatment or condition being manipulated. The control group serves as a baseline that enable you to ascertain the effect a treatment being tested has.
A(n) ____________ is a family-tree like representation of how organisms are related based on ____________ .
Answer: A PEDIGREE is a family-tree like representation of how organisms are related based on ANCESTRY. It shows genetic relatedness or blood relationship between individuals or organisms.
Explanation: Pedigree can be used to determine
1. Family history or genealogy.
2. Genetic or blood relationship.
3. Coefficient of relationship.
4. Degree of relationship.
5. Proportions of shared genes.
6. Mode of transmission of diseases.
7. Risk evaluation or determination.
Genetic counseling.
8. Linkage analysis.
Pedigree symbols are used in constructing pedigree.
The Griffith experiment showed that certain strains of Streptococcus bacteria could transform from one strain to another when combined. How did the Avery-MacLeod-McCarty experiment expand on Frederick Griffith's observations
Answer:
The options
A. It suggested that DNA is the
"transforming principle."
B. It confirmed that DNA is a double helix composed of two antiparallel strands.
C. It demonstrated that DNA consists of four nucleotides where the proportions of adenine/thymine and cytosine/guanine remain constant.
D. It proved that DNA is
semiconservative replication.
The CORRECT ANSWER IS A.
A. It suggested that DNA is the
"transforming principle."
Explanation:
A. It suggested that DNA is the
"transforming principle."✔
Griffith's experiments proved
that transformation can be seen in
pneumococcus, but gave no proof based on what molecular background the transformation was
WHILE, the Avery MacLeod-McCarty experiments proved that DNA was THE TRANSFORMING PRINCIPLE.
B. It confirmed that DNA is a double helix composed of two antiparallel strands.❌
These findings were established by James Watson, Francis Crick, Maurice Wilkins and Rosalind Franklin
C. It demonstrated that DNA consists of four nucleotides where the proportions of adenine/thymine and cytosine/guanine remain constant.❌
The findings was established by Erwin Chargaff.
D. It proved that DNA is semiconservative replication.❌
The findings was established by Matt Meselson and Franklin Stahl.
The Avery-MacLeod-McCarty experiment expanded on the Griffith experiment by identifying that DNA was the transforming factor which allowed one strain of bacteria to transform become another.
Explanation:The Avery-MacLeod-McCarty experiment expanded on the observations made in the Griffith experiment by identifying the specific substance that enabled the transformation of one strain of bacteria into another. In Griffith's initial experiments, he theorized the existence of a transforming factor but was unable to define what it was exactly. Avery, MacLeod, and McCarty, however, were able to demonstrate that this transforming factor was DNA. They did this by isolating the different components of the heat-killed bacteria strain involved in Griffith's experiment and individually exposed them to the living non-virulent strain. Only when DNA was introduced did transformation occur, pointing to DNA as the genetic material responsible for this change in characteristics.
Learn more about Avery-MacLeod-McCarty experiment here:https://brainly.com/question/37587163
#SPJ3
Fatter sociable weaver birds spend more time foraging where they are vulnerable to predation, are more attractive to predators, and are less likely to escape an attack. Conversely, thin birds risk starvation. Therefore, sociable weaver of an intermediate weight have a selective advantage. This is an example of ____ selection.a. frequent
b. directional
c. disruptive
d. stabilizing
e. mutational
Answer:
d. stabilizing
Explanation:
When the intermediate phenotypes have a better survival fitness and are better adapted to the prevailing conditions, natural selection favors them. Over the generations, the organisms having the intermediate phenotype reproduce more and leave more progeny. In this way, the proportion of the intermediate phenotype in the population is increased over time. This process is called stabilizing selection.
In the given example, the sociable weavers with intermediate body-weight have a selective advantage as they easily escape predators with their relatively light body and can withstand the starvation. Therefore, natural selection increases their proportion over generations. This represents an example of stabilizing selection.
Sociable weaver birds of an intermediate weight being favored is an example of stabilizing selection. This type of selection favors the average phenotypes and reduces genetic variance by selecting against extreme traits, thus maintaining the status quo of the population.
Explanation:Fatter sociable weaver birds spend more time foraging where they are vulnerable to predation and are more attractive to predators, making them less likely to escape an attack. On the flip side, thin birds risk starvation. Thus, sociable weaver birds of an intermediate weight hold a selective advantage. This scenario is an illustration of stabilizing selection, where natural selection favors the intermediate phenotypes and selects against the extremes. This mechanism tends to maintain the status quo and reduces genetic variance within the population by favoring those individuals whose traits are more average.
Similarly, in human infants, very high or very low birth weights are associated with greater risks, promoting an intermediate, optimal weight through stabilizing selection. Contrastingly, in the case of the peppered moth during the Industrial Revolution, the environment changed, resulting in directional selection. The darker moths were favored because they blended in with the soot-covered environment, increasing their survival rate and changing the population's phenotype over time.
If you were designing a cord for television using two materials with different levels of electrical conductivity, for safety you would place the substance with ________ conductivity __________ the cord.
lower ; outside.
Explanation:
Conductivity of a given material is the measure of electrical current that can pass through the material.
A good conductor has high conductivity while a bad conductor has lower conductivity.
Insulators have zero conductivity.
While preparing the cord the material with lower conductivity should be used to construct outer layer of the chord so that accidental electrical shock and short circuit could be avoided .
Every year in the United States, millions of pounds of herbicides, fungicides, and insecticides are applied to food crops. _____________________ make sure these products are safe for humans, other animals, and the environment.
Answer: Agricultural chemists
Explanation:Agricultural chemists make sure these products are safe for humans, other animals, and the environment. Engineers usually work with equipment used to apply the chemicals. Suppliers sell the chemicals that technicians apply. i got it right on USATESTPREP