Researchers conducted an experiment to identify the effects of three different hand sanitizers on the growth of bacteria. The researchers grew one type of bacteria in twenty-four identical covered petri dishes. Then, they opened eighteen petri dishes and applied the three hand sanitizers to six petri dishes each. They left the remaining six petri dishes closed as a control group. When the researchers measured the growth of bacteria two days later, the six dishes that had no hand sanitizer showed the least amount of bacterial growth. The researchers concluded that not using any hand sanitizer would lead to the least bacterial growth.
Which statement best explains why the researchers’ conclusion was not justified?
A. the experiment tested too many variables.
B. the control group was not treated the same as the experimental group.
C. the sample size of twenty-four petri dishes is not lathe enough.
D. the single type of bacteria i not adequate to making any conclusions.
Answer: LETTER A
Explanation: The experiment tested too many variables
how are mass and volume alike and what is density?
Some plants release toxic chemicals that kill or harm nearby plants. What type of example is this?
A. cooperation
B. mutualism
C. competition
D. parasitism
Answer: C. competition
Explanation:
Competition can be define as the ecological relationship in which one species is more superior over the other in deriving resources. In competition usually one species live and the population of other species may either decrease in abundance, or may extinct.
The release of toxic chemicals by the plants to harm nearby plants is an example of competition. This is because of the fact that the plants may face competition with other plants for resources such as sunlight, water and minerals. Therefore, a physiological response will be generated inside the plants so as to kill the neighboring plants.
A bowhunter's quarry is antelope, deer, black bear, or other big game of similar size or smaller. Which shot offers a good chance for a clean kill?
Answer:
quartering-away
Explanation:
Quartering away is a bow shot which is often referred to cleanly kill animals such as the antelope, deer, black bear or other big game animals that have a size similar to or are smaller than the ones mentioned.The quartering away shot is preferred because it provides a clear aiming point for the hunter and thus, the chances of success increases.During this shot, the situation is such that the animals are looking away from the hunter and thus, the animal is said to be quartering away. This kind of shot provides the biggest kill zone and the probability of success becomes high.A platypus has 26 types of chromosomes. How many total chromosomes would be present in an intestinal cell from a platypus?
What is the primary energy system to fuel cycling at 70% of VO2 Max for 15 minuets?
The oxidative energy system is the primary source of ATP for cycling at 70% of VO2 Max for 15 minutes, utilizing carbohydrates and fats due to the aerobic nature and duration of the activity.
The primary energy system to fuel cycling at 70% of VO2 Max for 15 minutes is the oxidative energy system. This system is best suited for activities like cycling that last longer than 2 minutes and up to several hours. Although the immediate energy system can generate ATP quickly for explosive activities lasting about 10-20 seconds, such as sprinting, and the anaerobic system can sustain high-intensity activity for roughly 1.3-1.6 minutes, cycling for 15 minutes at 70% VO2 Max falls well into the time range that depends mainly on the oxidative system. This system utilizes carbohydrates and fats to produce ATP, and it becomes the most efficient source of ATP production as the exercise duration exceeds 2 minutes and as the heart rate and breathing rate increase to supply more oxygen to the muscles.
Which of the following statements best describes the major difference between metaphase I of meiosis and metaphase of mitosis? (2 points)
In metaphase I, tetrad sets of homologous chromosomes stay together as they line up along the center of the cell.
In metaphase, homologous chromosomes are separated as each sister chromatid set is pulled to one end of the cell.
In metaphase, sister chromatids are separated and pulled apart to form a total of four new haploid cells.
In metaphase I, sets of sister chromatids line up at the center of the cell and the spindle fibers pull them apart.
In metaphase I, tetrad sets of homologous chromosomes stay together as they line up along the center of the cell.
If a pathogen on food got past saliva, which additional defenses in the first line of defense would the pathogen contact?
A stomach acid and lymphocytes
B lymphocytes and phagocytes
C phagocytes and mucus
D mucus and stomach acid
Ans. (D). mucus and stomach acid.
The first line of defense can be defined as the defense system that inhibits the entry of disease-causing pathogens or their components. It includes tears, skin, mucus, stomach acid, good bacteria, cilia, and neutrophils.
Pathogens present in food substances killed by antimicrobial substances present in saliva, mucus produced by epithelial lining of gastrointestinal tract, and stomach acid or hydrochloric acid. So, if a pathogen present in food got past saliva, it would be targeted by mucus and stomach acid.
Thus, the correct answer is option (D).
The first line of defence can be defined as the defence system that inhibits the entry of disease-causing pathogens or their members. It has tears, skin, mucus, stomach acid, good bacteria, cilia, and lymphocytes.
What is the first and second line of defense?The first line of protection is defined by the people on the front lines. They're driving risk, complying with regulations and standards, and taking out the company's defined risk management processes daily.
The second line of defence is executive and is liable for oversight of the doers.
Thus, option "A" is correct, stomach acid and lymphocytes.
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how have scientists determined the earth's core is composed of iron and nickel?
Final answer:
Earth's core is predominantly iron and nickel, inferred from seismic data, its density compared to the Earth's overall density, and its composition mirroring that of metallic meteorites. The solid inner and molten outer core composition, along with the generation of the Earth's magnetic field, supports a dense, metal-rich core.
Explanation:
Scientists have determined the Earth's core composition through various methods that overlap in the fields of seismology, geochemistry, and astrophysics. Seismic waves, created by earthquakes, have different speeds when they travel through solid and liquid matter, allowing scientists to characterize the inner and outer core. Observations show that the inner core is solid, primarily composed of iron and nickel, while the outer core is liquid, believed to be mostly molten iron potentially mixed with lighter elements such as sulfur and oxygen.
Another critical piece of evidence comes from the overall density of the Earth, as established by its gravitational effects and rotation, which suggests a denser metallic core when compared to the less dense surface layers. Additionally, the similarity in composition to metallic meteorites rich in iron and nickel supports the theory that these heavy elements sank to form the Earth's core during its early formation when the planet was still molten, and density stratification could occur.
Furthermore, the Earth's magnetic field, generated by the motion of electrically conductive material in the outer core, implies the presence of a metallic, iron-rich fluid. Laboratory experiments under conditions replicating the core's environment suggest iron alloys are conductive and match the observed density, thereby confirming a metal-based core and its role in geomagnetic phenomena.
If Tyler does not eat a diet that includes essential amino acid's hair cells will not be able to build
Must all species reproduce in order for the species to survive? A. No; plants don't reproduce, and they survive. B. No; not all species reproduce. C. Yes; without reproduction, living organisms would get lonely. D. Yes; without reproduction, once the living organisms died, there would be no offspring to replace them.
Answer:
Yes; without reproduction, once the living organisms died, there would be no offspring to replace them.
The statement "all species must reproduce in order for the species to survive" is definitely true. This is because without reproduction, once the living organisms died, there would be no offspring to replace them. Thus, the correct option for this question is D.
What is Species?Species may be defined as a group or collection of organisms that can significantly reproduce with one another in nature in order to produce fertile offspring normally. It will lead to the process of speciation as well.
According to the context of this question, the strategy of reproduction allows the organism to pass its genetic traits and characteristics to the next generation. This facilitates the species to exist by increasing its survival rate and reducing the chances of species extinction over time.
Therefore, all species must reproduce in order for the species to survive because without reproduction, once the living organisms died, there would be no offspring to replace them. Thus, the correct option for this question is D.
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what type of molecules diffuse through the cell membrane without using a channel protein ?
The molecules diffuse through the cell membrane without using a channel protein are as follows:
Gases (such as O₂ and CO₂), hydrophobic molecules (such as benzene), and small polar but uncharged molecules (such as H₂O and ethanol) are able to diffuse across the plasma membrane. Other biological molecules, however, are unable to dissolve in the hydrophobic interior of the phospholipid bilayer.Ions such as [tex]Na^+, K^+, Cl^-[/tex] can't get through due to their charge.Molecules such as glucose, sucrose, proteins, and starch cannot diffuse through cell membrane due to their large size.Learn more:
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Explain the statement “ nutrients do not flow in one direction in the ecosystem, they recycle through the ecosystem “
Nutrients in an ecosystem are constantly recycled and reused through a biogeochemical cycle, involving both living organisms and non-living components.
Explanation:The statement 'nutrients do not flow in one direction in the ecosystem, they recycle through the ecosystem' means that nutrients in an ecosystem are constantly being reused and recycled. They do not flow in a linear direction but instead go through a cycle, being passed from living organisms to non-living matter and back again. This recycling process is known as a biogeochemical cycle, which involves both the living organisms and the non-living components of the ecosystem.
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I REALLY NEED AN ANSWER! THANKS!
If a scientist creates a new rock-like substance in a laboratory, why wouldn’t this type of material be classified as a true mineral?
A.
It’s an inorganic substance.
B.
It’s not a naturally occurring substance.
C.
It’s too new to be a mineral.
D.
It would not be hard enough.
Answer:
B
Explanation:
What is a eukaryote, and when did eukaryotes first arise?
Eukaryote are cells with a nucleus an internal membrane-bound organelles probably evolved about 2 billion years ago.
What is the origin of eukaryotes?The leading hypothesis, called the endosymbiotic theory, is that eukaryotes arose as a result of a fusion of Archaean cells with bacteria, where an ancient Archaean engulfed (but did not eat) an ancient, aerobic bacterial cell.
What is meant by eukaryotic cell?Eukaryotes are organisms whose cells contain a nucleus and other membrane-bound organelles.
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Which one of these is not an example of intercellular communication?
A Bacteria share information about nutrients
B Ribosomes make protein
C Endocrine cells send hormones into blood
D Hypothalamus signals pituitary gland
A scientist conducted one trial of an experiment and got unexpected results. How can the scientist increase confidence in the results?
A by repeating the experiment several times
B by changing the experimental procedure
C by asking other scientists what they think about the results
D by modifying the results so they are close to the expected results
Answer:
A by repeating the experiment several times
Explanation:
One of the main characteristics of the scientific research is the ability of running the experiments with the same circumstances and context several times, in order to be able to confirm the results of the research and by doing this if sometime a scientist gets a result too far away from the expected he can run again the experiment to see if the experiment wasn´t compromised.
How was the grand canyon formed?
Where in this area would a lake or marsh most likely form? A. A B. B C. C D. D
Answer:
Option (B)
Explanation:
Lakes and marshes are generally formed in the areas where the elevation is less. They are the region where the water bodies remain stagnant i.e. no flowing of water takes place. These are not a part of the huge oceans and are usually surrounded by land on all the sides. They can be comprised of salt water or fresh water and are comparatively larger than ponds in terms of size.
Thus, the point B is the most favorable location for the formation of lakes and mashes as it is located near the mean sea level.
Hence, the correct answer is option (B).
Scientists believe that the Earth's early atmosphere lacked __________ gas because photosynthetic organisms did not yet exist
The right answer is C. Oxygen
During photosynthesis, there is consumption of carbon dioxide and water to produce glucose and dioxygen. Glucose is the "fuel" of its growth. Cellular respiration will consume some of this glucose and oxygen to form oxygen and water.
So, if the atmosphere was lacking oxygen, it's simply because there was no photosynthesis producing oxygen.
Which description states a characteristic property of the noble gases?
A.
relatively unstable
B.
highly reactive
C.
colorful and shiny
D.
very stable
which of these elements is essential to making up all organic molecules?
A. hydrogen
B oxygen
c. carbon
d nitrogen
Answer:
carbon
Explanation:
The four fundamental types of organic molecules are proteins, carbohydrates, lipids, and _____________. Question 14 options: phosphates salts nucleic acids sulfates
Answer:Nucleic acid
Explanation:
The four Fundamental types of organic molecules are
proteincarbohydrateslipidsNucleic acidNucleic acids are bio polymers composed of Nucleotide, very complex and large organic molecules.Nucleic acid is divided into four different levels
primarysecondaryTertiaryQuaternaryExamples of Nucleic acids are DNA,RNA.
Grasses → mice → cat → coyote As matter and energy move from grasses to coyotes the amount of available energy
a) Always decreases and population size always increases
b) Always increases and population size always decreases
c) Always decreases but population size may increase or decrease
d) Increases or decreases but population size remains the same
Answer:
The most reasonable answer would be c.
Hope I helped:)
Explanation:
what are the correct labels for this diagram of glucose catabolism
Glucose catabolism entails breakdown of glucose and other simple sugars to release energy initiated in a process called glycolysis. Energy is extracted and stored in the form of ATP and NADH. The diagram representing this process should include glucose, ATP, NAD+, pyruvate and two stages of glycolysis.
Explanation:Glucose catabolism, also known as glycolysis, is represented in a diagram showing the breaking down of glucose (a six-carbon sugar) to extract energy. The labels for this diagram would likely include glucose, ATP, NAD+, ADP, P; because glucose, in combination with ATP, NAD+ and inorganic phosphate, breaks down into pyruvate, introducing ATP and NADH. The output of this process is two pyruvate molecules, two ATP molecules, and two NADH molecules.
Another relevant detail here is the incorporation of the simple sugars including galactose, fructose, glycogen, and pentose which are catabolized during glycolysis. Amino acids connect to this process through pyruvate, acetyl CoA, and components of the citric acid cycle. In aerobic conditions, pyruvate enters the Krebs cycle, leading to the production of high-energy FADH2 and NADH molecules which provide electrons to the oxidative phosphorylation process, generating more ATP molecules.
In your diagram, you should also indicate the two phases of glycolysis. The first part includes trapping of the glucose molecule in the cell and using energy to modify it so that it can be split into two three-carbon molecules. In the second phase, energy is extracted from the molecules and stored in the form of ATP and NADH. All these elements make up an accurate diagram of glucose catabolism.
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A scientist was observing a population of sea cucumbers in coastal waters. Over a 10-day period, she collected the following information about the distribution of the individuals within a 10-meter square plot:
Distribution of Sea Cucumbers within a 10-Meter Square Plot
Time of Day Average Distance between Individuals (cm)
Midnight 7.0
4 a.m. 7.8
8 a.m. 43.7
Noon 172.0
4 p.m. 349.5
8 p.m. 58.9
Midnight 7.0
Use the data above as a basis as you answer the following questions:
(a) Identify THREE biotic or abiotic factors that could cause the sea cucumbers to vary their distance from each other throughout the day. (b) Using one of the factors listed in part (a) as an independent variable, write a hypothesis that proposes how this variable could cause the sea cucumbers to vary their distance from each other. (c) Design a procedure for a controlled experiment to test your hypothesis. (d) Describe the results that would support your proposed hypothesis and the results that would refute your hypothesis.
The abiotic factors that could cause the sea cucumbers to
differ their distance from one another are temperature, time of the day, and
humidity. The biotic factors that could influence are the organisms around
these creatures. Furthermore, the independent variable in this study is the
time of the day where observed are the average distance between these sea
creatures and their output, the distribution of sea cucumbers as the dependent
variable.
Hypothesis: There is a link between the time of the day and the distance of sea cucumbers amongst each other.
what is the main component of the cell membrane? a. lipids b. carbohydrates c. cholesterol d. proteins
The main component of the cell membrane is lipids, specifically phospholipids. Hence, option a is correct.
Phospholipids form the core structure of the membrane, creating a bilayer that provides the basic fluid framework. However, it's important to note that other elements such as cholesterol, proteins, and carbohydrates also play crucial roles in the function and structure of the cell membrane. Cholesterol, for example, while also a lipid, helps to modulate the fluidity of the membrane and is found alongside the phospholipids. Proteins account for about 50% of the membrane's composition by mass and are involved in various functions such as transport, signaling, and structural support. Carbohydrates, comprising around 10% by mass, are attached to the exterior surface of lipids and proteins, playing key roles in cell recognition and adhesion as components of glycolipids and glycoproteins.
What would happen to the circulatory system if the muscular system stopped working?
The muscular system aids in your ability to move, speak, and breathe.
What is Circulatory system?You would become entirely paralyzed if your muscular systems stopped working, and you would eventually cease breathing, which would result in no oxygen getting to your brain and decreasing blood pressure, which would finally lead to circulatory system failure and your death.
Since the muscular system regulates breathing and the circulatory system relies on oxygen to support the heart and other critical organs.
Blood arteries in the circulatory system move blood away from and toward the heart. Blood leaves the heart through arteries and returns through veins.
Therefore, The muscular system aids in your ability to move, speak, and breathe.
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Select all of the answers that apply.
Which statements are true regarding the cosmological principle?
The universe looks the same from all directions, but can change and evolve over time.
The universe looks the same from all directions, and hasn't and won't change or evolve over time.
The universe can't be studied scientifically because scientists can't directly test their hypotheses.
Scientists can study the universe because the cosmological principle suggests that any physical laws or processes are the same for the entire universe.
What stage of cellular respiration does not involve any carbon-based compounds as a reactant or product? Electron transport chain Krebs cycle Glycolysis Fermentation
Answer:
Option A , Electron transport chain
Explanation:
In Electron transport chain(ETC), no carbon based reactant or product are involved.
Usually in ETC (taking place in the inner membrane of the mitochondria), NADH and FADH2 releases high-energy electrons. Some energy of these electrons is capture while passing through the chain. This stored energy is then used for pumping hydrogen ions into the intermembrane space from the matrix.
Since in this entire process no carbon element is involved and hence, option A is correct