The best explanation for the relationship between HbS allele frequency and malaria endemicity in Africa is that in holoendemic areas, b) where malaria is prevalent, the HbS allele frequency is higher (between 0.52 and 4.04) due to natural selection favoring its resistance to malaria. In contrast, in malaria-free zones, the frequency remains low (between 0 and 2.02) as there is no selective benefit to the allele.
The relationship between HbS allele frequency and malaria endemicity in Africa is influenced by natural selection due to malaria resistance. Individuals with the HbS allele have sickled erythrocytes that are poor hosts for the malaria-causing Plasmodium parasite, therefore they have a survival advantage in malaria-endemic areas. Consequently, in regions with high malaria incidence such as holoendemic areas, the HbS allele frequency is higher due to natural selection preferring traits that confer resistance to malaria. However, in malaria-free areas, there is no selective advantage to having the HbS allele, and therefore its frequency remains lower.
Applying this knowledge to the provided statements, the best explanation is that b) when an area is holoendemic, the HbS allele frequency is between 0.52 and 4.04. This range indicates a higher prevalence of the HbS allele where malaria is widespread. On the other hand, when an area is malaria-free, the advantage of having the HbS allele disappears, resulting in much lower frequencies which would be between 0 and 2.02.
True of false absolute magnitude takes distance into account when indicating the surface temperature of a star
This is false, it takes distance into account for brightness
Given the history of corn in the western hemisphere, what would be the best strategy for survival of the Zea species?
The answer is C) Increase genetic variation and breed plants to contain the wild variety.
Which of the following is a protein maintained at constant levels throughout the cell cycle that requires cyclinto become catalytically active?
A) PDGFB) MPFC) protein kinaseD) cyclinE) Cdk
The answer is; E
CDK is only active when they bind cyclin. In the CDK-cyclin complex, they are able to phosphorylate their substrates on serines and threonines. Particular CDKs are specific to their cell cycle phase. CDKs have maintained more or less constant levels in a cell and the cyclin levels are what fluctuate.
Cdk, or Cyclin-Dependent Kinase, is a protein that is maintained at constant levels throughout the cell cycle and requires cyclin to become catalytically active. It is a key regulator of the cell cycle.
Explanation:The protein that is maintained at constant levels throughout the cell cycle and requires cyclin to become catalytically active is Cdk (Cyclin-Dependent Kinase).
Cdks are a type of protein kinase and are key regulators of the cell cycle. They are present in the cell at constant concentrations and their activity is controlled by the synthesis and degradation of their regulatory subunits, the cyclins.
As cyclin levels increase, the Cdk-cyclin complexes are formed and become active, which helps push the cell through different stages of the cell cycle.
The protein that requires cyclin to become catalytically active and is maintained at constant levels throughout the cell cycle is protein kinase.
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Which of the following groups in the Domain Archaea require high salt concentrations for survival?
hyperthermophiles
halophiles
Archaezoa
methanogens
The correct answer is: halophiles
Halophiles on Greek means "salt-loving", so organisms that belong to this group are extremophiles (survive in extreme environment) that live in high salt concentration. Halophiles usually belong to Archaea, but can be found in Bacteria domain and sometimes even Eukarya.
Halophiles can survive on very salty environments (with a concentration of salt that is five times greater than the salt concentration of the ocean.
if a dna molecule is made up of 20% thymine what percent of it would be adenine
20% beacuse adinine always pair with thymine therefore the percentage of adinine and thymine is 20+20 = 40% , thus the remaining 60% is of guanine and cytosine
How does a selectively permeable membrane affect diffusion?
- All molecules move from a lower concentration to a higher concentration.
- Only some molecules move from a higher concentration to a lower concentration.
- Only some molecules move from a lower concentration to a higher concentration.
- All molecules move from a higher concentration to a lower concentration.
Answer:
- Only some molecules move from a higher concentration to a lower concentration.
Explanation:
Selective permeability of the membrane means that membrane regulates which molecules (ions, substances) and how much of them can pass through it. Permeabilty of the membrane is determinated by its structure (hydrophobic heads and hydrophilic tails, cholesterol), temperature
The simplest form of transport through membrane is diffusion, passive transport of the molecule down its concentration gradient 9from higher to lower concentration). Some molecules can move down their concentration gradients directly, some have to pass through membrane proteins in a process called facilitated diffusion while others require energy and use active transport.
What brings the proper amino acid to the ribosome
jjjjjjjkjkjkjkjljlkjl
Which of the following phenomena will be observed if a cell's membrane is pierced?
(a) the membrane reseals
(b) the membrane collapses
(c) a tear is formed
(d) the membrane expands
a) the membrane reseals
The membrane reseals, The correct answer is A.
Glucocorticoids do which of the following?
1. promote the release and breakdown of fatty acids
2. increase blood glucose levels
The answer is 2
Medications known as glucocorticoids (prednisone and cortisone, etc). are known to have a side effect that increases blood glucose (sugar) since these drugs promote glucose production in the liver.
The M-phase checkpoint ensures that all chromosomes are attached to the mitotic spindle. If this does not happen so it will most likely be arrested in
a. Telophase
b. Prophase
c. Pro metaphase
d. Metaphase
Answer:
D. Metaphase. It is the third of the five phases of biological cell division, or more specifically, the division of what is inside that cell's nucleus.
Explanation:
The M-phase is the most dramatic period of the cell cycle, involving a major reorganization of virtually all cell components.
Color blindness is a recessive trait. The gene for color blindness is on the X-chromosome. The family tree below shows the trait of color blindness. The only unknown is the mother in the first generation. What is true about the mother?
B,
since males only need one recessive trait for it to show, and the father is not colorblind, the mother at least has to be a carrier for the colorblindness trait.
The true statement about the mother of this family tree is that she is a carrier for color blindness.
The correct option is (B).
What is color blindness?Color blindness is a disability in which you are unable to see colors normally. Color deficiency is another name for it.
It is a condition in which a person is unable to distinguish between different colors.
The most common colors are greens and reds, but it can also happen with blues.
This condition is only dominant in males, but females carry this disability as recessive carrier, so they can transfer this gene to the next generation.
Thus, option (B) she is a carrier for color blindness is correct.
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Axel draws a cladogram containing a zebra, bear, lion, and tiger. He uses the physical appearances of the animals to decide where they should be placed in his cladogram. Is he correct? Why or why not?
A cladogram containing a zebra, bear, lion, and tiger, should look like this:
mammalia
I I
carnivora perissodactyla
I I I
arctoidea feliformia equidae
I I I
ursidae felidae equini
I I I
ursus pantherinae equus
I
panthera
I I
panthera tigris panthera leo
All four animals are part of the mammals, thus it is the closest relation they all have. Further, the lion, tiger, and bear are part of the carnivores, while the zebra is part of herbivores, thus purring the first three to be more closely connected. The bear than diverges into its own family, while the lion and tiger remain in the same, thus making them the most closely related. So we have the lion and tiger to be the closest, than comes the bear, being closer to them then to the zebra, and then comes the zebra which is connected with the other three much further back in the past.
Becky's 2-year-old son can't walk because he was born with spina bifida. to reduce the chances that her next baby is born with this birth defect or related disorders, becky should _____.
Not have kids, adopt them, or maybe find a different dad if her carriers the disease. She should follow normal check ups. She should take 400mg of folic acid to help the spin grow better. A multi-vitamin and some vitamin B would reduce it by 70%
Consider the following sentence: "The dog did not eat." Which of the following variations of this sentence is most like a frameshift mutation?The did not eat.The did dog not eat.The dod idn ote at.The dog did dog did not eat.
The answer is D. . . . . . . . . .
The sentence 'The dod idn ote at' most resembles a frameshift mutation. A frameshift mutation happens when the reading frame of a gene is shifted, resulting in a completely different translation, similar to the shift and change in meaning in this sentence.
Explanation:The variation most like a frameshift mutation is "The dod idn ote at." In biology, a frameshift mutation is a type of mutation involving the insertion or deletion of a nucleotide in a DNA sequence that is not divisible by three. Frameshift mutations result in a completely different translation from the original because the reading frame of the gene is moved. This change is similar to what happens in the given sentence, where every word has had a letter moved, shifting the entire sentence and changing the meaning.
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What is the final electron acceptor in the light reactions?
The final electron acceptor is NADP.
The light-dependent reactions is one of the two successive phases that occur during photosynthesis (other is light-independent reactions). The light-dependent reactions use sunlight energy to make the energy storage molecule ATP and the reduced electron carrier NADPH. In the light-independent reactions (also called Calvin cycle), CO2 is absorbed and fixed in order to build three-carbon sugars (glyceraldehyde-3-phosphate) and this process is fueled by, ATP and NADPH from the light reactions.
If crossing over occurs between two chromatids on a single pair of homologous chromosomes, how many gametes will have a recombinant phenotype?
all 4
1 of the 4
2 of the 4
3 of the 4
none of them
If crossing over occurs only between two chromatids, these crossover chromosomes produce the recombinant gametes and the remaining two are similar to the parentals.
The answer is a
If crossing over occurs between two chromatids on a single pair of homologous chromosomes, then the number of gametes which will have a recombinant phenotype will be 2 of the 4. Thus, the correct option is C.
What is Crossing over?Crossing over is a cellular process which takes place during the meiotic division when the chromosomes of the same type in the cell are lined up. When two chromosomes, one from the mother side and one from the father side line up, then some part of the parental chromosome can be switched between the two parents. The two chromosomes contain the same genes, but may have different forms of the genes with them.
If crossing over occurs between any two chromatids which are present on a single pair of homologous chromosomes in the cell, then two out of the four resulting gametes will have a recombinant chromosome and two will have the parental chromosome.
Therefore, the correct option is C.
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In plants, what nucleotide would you expect to immediately follow a methylated cytosine?
Transportation water and minerals from the roots to the leaves in plant is through
Osmotic movement from the roots to the leaves
The elongated part of a neuron that is normally covered by a myelin sheath is known as the _[blank]_.
dendrite
synapse
node of Ranvier
axon
The myelin sheath insulates the axon
Select the statement that is true concerning primary teeth.
There are 27 primary teeth, and the molars are permanent.
There are 32 primary teeth, and most children lose these teeth due to decay because they are never very strong.
There are 20 primary teeth, and by 24 months of age most children have all 20.
There are 24 primary teeth, and no new primary teeth appear after 13 months.
The correct answer is: There are 20 primary teeth, and by 24 months of age most children have all 20.
Primary teeth also known as deciduous teeth, milk teeth, are the first set of temporary teeth in the growth development of humans. They develop during the embryonic stage of development, become visible in the mouth during infancy (erupt) and usually get replaced by permanent teeth around age six (the first tooth). The primary teeth consist of 4 central incisors (one in each quadrant), 4 lateral incisors, 4 canines, 4 first molars, and 4 secondary molars.
There are 20 primary, or 'baby', teeth that most children have by the age of 24 months. These temporary teeth eventually fall out and are replaced by 32 permanent adult teeth.
Explanation:The true statement concerning primary teeth is: There are 20 primary teeth, and by 24 months of age most children have all 20.
Primary teeth, also known as 'baby teeth', begin to erupt in infants around 6 months of age and continue until about 24 months of age. These teeth are temporary and eventually fall out to be replaced by permanent teeth, which number 32 in total in an adult mouth.
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At what point in the light-capturing reactions is the electromagnetic energy of light converted into chemical energy? Where does this occur?
The conversion of light energy to chemical energy first occurs when electrons are transferred from excited photopigments to an electron carrier in a photosystem (pigments together with proteins organized into complexes and located in the thylakoid membranes of chloroplasts).
The light-dependent reactions is one of the two successive phases that occur during photosynthesis (other is light-independent reactions). The light-dependent reactions use sunlight energy (electromagnetic radiation) to make the energy storage molecule ATP and the reduced electron carrier NADPH. In the light-independent reactions (also called Calvin cycle), CO2 is absorbed and fixed in order to build three-carbon sugars (glyceraldehyde-3-phosphate) and this process is fueled by, ATP and NADPH from the light reactions.
Which of these structures is found in the stomach but nowhere else in the alimentary canal?a. a circular muscle layerb. mucus-forming cellsc. a lining of columnar epotheliumd. an onblique muscle layer
Answer:
d. an onblique muscle layer
Explanation:
The alimentary canal has four main layers:
Mucosa (innermost layer which surrounds the lumen), submucosa (connective tissue with blood vessels, lymphatics, and nerves), muscular layer, serosa ( outermost layer of connective tissue).
Muscular layer is subdivided into:
• the inner- arranged in circular rings, prevents food from travelling backward
• outer layer- arranged longitudinally, shortens the tract.
The stomach has an extra layer called inner oblique muscular layer (churning function).
Which of the following choices best describes dopamine?
A substance that is naturally found in the brain.
An illegal drug that can cause great damage.
A receptor molecule that is found on neurons.
A protein that stimulates neurons to grow.
i think the answer is
a substance that is naturally found in the brain
It is important to understand the differences between chemical and physical changes which process is an example of a physical change
Answer:
The question lacks options, the options are:
A) Water turns to steam when boiled over a Bunsen burner.
B) Carbon combines with oxygen to form carbon dioxide gas.
C) Water breaks down into hydrogen and oxygen gases.
D) Limestone breaks down into lime and carbon dioxide when heated.
The answer is A
Explanation:
Changes occur from one state of matter to another. This change can either be physical or chemical. A physical change is a change in which no new substances are formed as products and it can be reversed to form the reactants again. Chemical change, on the other hand, forms new substances as products by the rearrangement of chemical bonds in the resulting molecule.
In the case of this question, water turning into steam when heated, a process called evaporation is an example of physical change because water, which is a liquid is just changing its state to gaseous (steam). Hence, no new substance is formed. The steam can easily be reversed back to water via CONDENSATION.
In the other options, new products are formed either by breaking the chemical bonds between molecules or rearranging them. Hence, options B, C and D are examples of chemical change.
What is the role of the sodium-potassium pump in the nervous system?
Stimulated by the action of the ions on its receptors, the pump transports them in opposite directions against their concentration gradients. ... The sodium-potassium pump carries out a form of active transport—that is, its pumping of ions against their gradients requires the addition of energy from an outside source.
If Marie and Calvin dissolve 50 grams of KBr in 100 grams of water at 90oC, the solution is A) saturated B) semisaturated C) supersaturated D) unsaturated
Answer:
Its D. Unsaturated on USATestprep. By the way, there is no such thing as semisaturated.
Answer: Option (D) is the correct answer.
Explanation:
It is known that density of water or 100 grams of water is 1 g/ml. As density is mass divided by volume then it is known that in 100 grams of water 99.2 grams of KBr can be dissolved at [tex]90^{o}C[/tex].
Therefore, it is obvious that solution will be unsaturated because 50 grams of KBr will completely dissolve in it.
As saturated solution is a solution which is unable to dissolve more solute. Whereas a solution is unsaturated when solute dissolves in it until the saturation point.
Hence, we can conclude that if Marie and Calvin dissolve 50 grams of KBr in 100 grams of water at 90oC, the solution is unsaturated.
According to Max Weber, what factor or factors are responsible for social stratification?
A. caste, prestige, and power
B. class, prestige, and power
C. only a person’s prestige
D. only a person’s economic position
According to Max Weber, what factor or factors are responsible for social stratification?
B. class, prestige, and power
~Hope this answers your question!~
Max Weber cited class, prestige, and power as the key factors responsible for social stratification, which are interconnected yet distinct elements influencing an individual's social standing. The correct option is: B. class, prestige, and power.
According to Max Weber, the factors responsible for social stratification are class, prestige, and power. Weber's comprehensive theory of social stratification encompassed not only economic positioning but also the dimensions of status and the ability to influence others.
Weber acknowledged that while wealth, power, and prestige frequently go hand-in-hand, they do not always overlap and must be considered as separate yet interconnected factors contributing to an individual's social standing.
Feather color in budgies is determined by two different genes, y and b, one for pigment on the outside and one for the inside of the feather. yybb, yybb, or yybb is green; yybb or yybb is blue; yybb or yybb is yellow; and yybb is white. two blue budgies were crossed. over the years, they produced twenty-two offspring, five of which were white. what are the most likely genotypes for the two blue budgies?
Answer:
bbbb and ybyb
Explanation:
Since blue is dominant and white is recessive,, one blue present will result in blue feathers. byyy will also result in a blue bird.
Answer:
Option E
Explanation:
Please see the attachment
Which of the following hormones stimulates pancreatic secretions?
-histamine
-motilin
-gastrin
-secretin
The correct answer is: secretin
Secretin is a peptide hormone (produced in the S cells of the duodenum), that regulates secretions in the stomach, pancreas, and liver. Secretin is secreted in response to acid in the duodenum, so its role is to stimulate duct cells of the pancreas to secrete water and bicarbonate (regulating water homeostasis).
Secretin is the hormone that stimulates pancreatic secretions.
Explanation:The hormone that stimulates pancreatic secretions is secretin. Secretin is produced by the duodenum in response to the presence of acid in the stomach. When secretin is released, it stimulates the pancreas to secrete bicarbonate into the small intestine to neutralize the acid. This helps to maintain an optimal pH for digestion in the small intestine.
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Which statement about the kidney and water is correct?
The kidney removes some water from the blood by filtration, after which water is not reabsorbed.
The kidney first removes some water from the blood by reabsorption, and then returns water to the blood by filtration.
The kidney removes water from the blood by reabsorption only; water is not removed by filtration.
The kidney first removes some water from the blood by filtration, and then returns water to the blood by reabsorption.
Answer:
The kidney first removes some water from the blood by filtration, and then returns water to the blood by reabsorption.