In those parts of equatorial Africa where the malaria parasite is most common, the sickle-cell allele constitutes 20% of the b hemoglobin alleles in the human gene pool. In the United States, the parasite that causes malaria is not present, but African-Americans whose ancestors were from equatorial Africa are present. What should be happening to the sickle-cell allele in the United States, and what should be happening to it in equatorial Africa

Answers

Answer 1

Answer:

directional selection, stabilizing selection

Explanation:

Directional selection is a type of natural selection that favors one extreme phenotype over other phenotypes, thereby modifying allele frequency in the direction of the favored phenotype. This type of positive selection is the main cause of phenotypic diversification. In the USA, the environment created a selection pressure that favored individuals that don't have the defective sickle-cell allele, thereby reducing its frequency in this population. Stabilizing selection, also known as balancing selection, is a type of natural selection where the most common phenotype is selected in the population, thus predominating in future generations. In equatorial Africa, the defective sickle-cell allele is present in a high frequency because individuals that are heterozygous for this allele are less susceptible to malaria, and therefore balancing selection should maintain this allele in the African population.


Related Questions

Earth makes one full rotation on its axis approximately every 24 hours. If Earth's period of rotation decreased to 20 hours, which of the following changes would occur?


There would be fewer days in a week.


The length of nighttime would increase.


It would take Earth longer to revolve around the Sun.


The length of daylight and nighttime would decrease.

Answers

Answer:

The length of daylight and nighttime would decrease.

Explanation:

If 24 hours was decreased to 20, it would shorten night and day time.

The picture shows respiratory epithelium in the lungs. The cilia, or fingerlike projections are MOST LIKELY there to
A)
move liquid.
B)
catch debris.
C)
secrete mucus.
D)
transmit impulses

Answers

Answer:

B. catch debris in the lungs

B. Catch debris would be the answer

triangular shaped land mass found on land ​

Answers

Answer:

beautiful

Explanation:

serioudly I like it

Deltas are beautiful landforms, especially when viewed from above. Roughly triangular in shape, deltas are full of complex, wonderful detail: swirling, multi-colored sediments broken by serpentine, miniature river channels.

In mitosis, parent cell(s) divide into daughter cell(s).

Answers

Answer: yes, mitosis is simple cell division

Explanation: mitosis is the process by which a cell divides into two cells, each with DNA from the duplication of the two original strands (in eukaryotes, duplication of all chromosomes).

Answer:

One, two

Explanation:

When ONE parent cell divides, it divides into TWO daughter cells.

Distinguish relative dating from absolute dating.

Answers

Answer:

Explanation:

Relative age is the age of a rock layer (or the fossils it contains) compared to other layers. ... Absolute age is the numeric age of a layer of rocks or fossils. Absolute age can be determined by using radiometric dating

Place the following molecules in order of size (smallest to largest): glucose, water, starch. What evidence helped you determine the answer?

Answers

I have a lot to say to my mom that I don’t

4. How does temperature affect chemical weathering?
A. It is an agent of weathering.
B. It affects the amount of oxygen involved in weathering.
C. It affects the rate of weathering.
D. It affects the type of weathering.

Answers

Answer:

C.

Explanation:

It affects the rate of weathering.

Modern whales evolved from mammals that lived on land. Fossil evidence reveals that one characteristic that has changed over time is the position of whales nostris. The images below show the skills of a modern whale
and its ancestor, Pakicatus
Nostrils at front
of skull
Nostrils at top
of skull
Pakicetus
Eschrichtius
cientists think that the position of the nostrils gives modern whales an evolutionary advantage. Which of the following most likely describes how this adaptation is advantageous?
O The nostril position allows whales to obtain air more easily at the surface of the water.
The nostril position allows whales to obtain food more easily at the surface of the water.
O The space lett empty by the migrating nostrils has allowed modern whales to develop gills.
The space left empty by the migrating nostrils has allowed modern whales to develop teeth.

Answers

Answer: Its A my friend, how it helps!.

Explanation: I just completed the Test.

The nostril position allows whales to obtain air more easily at the surface of the water is most likely describes the advantage of adaptation.

What do you mean by adaptation?

In biology, adaptation has three related meanings. It is the dynamic evolutionary process of natural selection that fits organisms to their environment, enhancing their evolutionary fitness. Secondly, it is a state reached by the population during that process.

The ability of living organisms to adjust themselves to their surroundings is called adaptation. Adaptations are the changes in structure or behaviour of an organism that will allow the organism to survive in that habitat.

Adaptations are unique characteristics that allow animals to survive in their environment. There are three types of adaptations: structural, physiological, and behavioral.

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why does food get cold but drinks get hot​

Answers

Answer:

it might be because of the room temperature.

Explanation:

since drinks are colder than the room temperature they will get warmer to be the same as the room temperature and because food is hotter than room temperature it gets colder to be the same as the room temperature. dont quote me on that just a guess

Zara had a birthday and was able to choose a pet. The pet that she chose was a beautiful clownfish named Bozo, a common salt water fish. Zara already has a tank with goldfish at home. Use your knowledge of diffusion & osmosis to tell Zara how to take care of Bozo.

Answers

Answer:

See the answer below

Explanation:

The advice I would give  to Zara would be that she should keep Bozo in a separate tank with common salt water away from the goldfish. Bozo is a salt water fish while the goldfish can only survive in freshwater.

If Bozo is kept in a saltless water/freshwater tank with the goldfish, the water would be hypotonic to Bozo. Consequently, water will osmotically diffuse into the cells of Bozo, the cells would become turgid and lyse, and this would lead to the death of the fish.

If the goldfish is kept in the same salt water tank with Bozo, the salt water would be hypertonic to the goldfish. Consequently, water will osmotically diffuse out of the cells of the goldfish into the surrounding salt water, the cells of the goldfish would become flaccid, and this would lead to the death of the fish.

how did advancements in technology help scientists better understand process of cell division?

Answers

Answer:

As is true for many fields of research, cell biology has always been ... Thanks to these advances we now have access to microscopes and ... You might then also realize that the new method, at least on paper, may have additional applications. ... which makes the technology attractive to yet more scientists.

Explanation:

Hoped I helped you out please mark me brainliest!!!

With the creation of the microscope, humans were able to observe plant and animal cells, and as technology advanced, scientists were able to learn more about these various types of cells.

What is a microscope?

A microscope is a device that can be used to examine small objects, including cells. The image of an object is magnified in the microscope by at least one lens.

In most cases, the light is focused on the sample by passing it through a condenser.

After passing through the sample, the light passes through the objective lens, which magnifies the image of the sample, and then to the oculars, where the enlarged image is viewed.

The discovery of the green fluorescent protein (GFP), the development of increasingly sophisticated microscopes, and the development of in vitro assays that faithfully reproduce cellular functions are just a few examples of technological advances that have fueled many areas of cell biology.

Thus, it can be concluded that the advancements in technology help scientists better understand process of cell division.

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23. In both plant and animal cells, the cell
membrane
(1) produces enzymes
(2) controls reproduction
(3) is composed of sugars

(4) regulates diffusion

Answers

Answer:

the answer is option 1

The Cell membrane regulates diffusion, in plants and animal cells.

What is a Cell Membrane?Every biological cell has a thin membrane that separates it from the rest of the environment this membrane is known as a cell membrane.Cell membranes is made of lipids and proteins.The cell membrane's chemical nature makes it extremely flexible, making it a perfect border for quickly growing and dividing cells.Cell membrane is a semi-permeable membrane.

Cell membrane does not produce enzymes.

Hence, the option (1) is incorrect.

Cell membrane cannot control reproduction.

Hence, option (2) is incorrect.

The main constituents of cell membrane is lipids and proteins, not sugars.

Hence, option (3) is incorrect.

Cell membrane regulates diffusion, because the cell membrane contains the semi-permeable membrane which allows only lipids and certain small molecules in the cell.

Hence, option (4) is correct.

Therefore, the Cell membrane regulates diffusion, in both plants and animal cells.

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How does increasing plant biomass (amount of plants) affect atmospheric CO

Answers

Answer:

Since there are more plants more carbon dioxide is being removed because plants are carbon reservoirs.

Explanation:

Describe endocytosis, phagocytosis, pinocytosis, and exocytosis.

Answers

Answer:

Endocytosis: Endocytosis is the process by which cells take in substances from outside of the cell by engulfing them in a vesicle.

Phagocytosis: Phagocytosis, process by which certain living cells called phagocytes ingest or engulf other cells or particles.

Pinocytosis: Pinocytosis, a process by which liquid droplets are ingested by living cells.

Exocytosis: Exocytosis is the process by which a large amount of molecules are released; thus it is a form of bulk transport.

Explanation:

Summarize the roles of glucose and ATP in
energy processing.

Answers

Answer:

Summary. Glucose is the carbohydrate produced by photosynthesis. Energy-rich glucose is delivered through your blood to each of your cells. ATP is the usable form of energy for your cell

Skim the headings and bold words in this section. Write four steps scientists might take to solve a problem.

Answers

Answer:

1) Create a hypothisis 2) Create experiment 3) collect data 4) write conclusion

The four steps that a scientist uses to solve a problem are creating hypothesis, experiment, data sorting and writing conclusion.

What are hypothesis?

A hypothesis is an elaboration posited for a characteristic. The scientific technique requires that a hypothesis be testable in order for it to be considered a scientific hypothesis.

Scientists typically base scientific hypotheses on previous findings that cannot be adequately explained by existing scientific theories.

Any process that co-ordinate system data into some defined order to make it simpler to understand, analyze, or visualize is referred to as data sorting.

The conclusion is the final section of an academic essay. The conclusion should restate your response to the question and briefly summarize key points. It does not contain any new points or information.

A scientist solves a problem by developing a hypothesis, conducting an experiment, sorting data, and writing a conclusion.

Thus, by using these steps, scientist can come to an end for the problem.

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Explain the difference between how light falls on the Earth near the Equator or the Poles

Answers

Answer:

Explanation:

The normal amount of solar radiation reduces from the Equator to the poles. This is because the low latitudes (near the Equator deliver relatively large amounts of radiation all year, and at high latitudes (near the poles), the more slanting angle of the Sun’s rays together with long periods of darkness in the winter, result in a low amount of received radiation.

Artificial selection applies only to dog breeding?

True OR False.

Answers

Answer:

Domestication is the act of separating a small group of organisms (wolves, in this case) from the main population, and select for their desired traits through breeding. ... Dog breeding is a perfect example of how humans select for desirable or fashionable traits.

true...?

Explanation:

Answer:

False.

Explanation:

The bananas we have today were created using artificial selection. Same thing with peanuts by the way.

Order the levels of organization of living things. (Order the levels starting from top to bottom with the smallest at
the top)
biome
species
biosphere
population community
ecosystem


WILL GIVE BRAINLIEST

Answers

1 population
2 species
3 economists
4 biome
5 biosphere

Whats the answer giving brainliest HELP!!!!!

Answers

Answer:

I feel like the first one is the best

Explanation:

widening the roads will just cause more cars.

raising the price is most likely not gonna help but its an option.

expanding just means more cars

Provide at least 1 example of a mutation
that does not have a negative effect on
the individual.
PLEASE HELP ME

Answers

i honestly don’t know but i’m guessing maybe having more fingers or something


If a strand of
DNA reads ATC
C, what would
the other side
read?

Answers

Answer:

TAGG

Explanation:

Adenine always pairs with thymine and cytosine always pairs with guanine

Please also describe how actin-binding sites are made available for cross-bridging with myosin heads during contraction.

Answers

Answer: The calcium ion binds to troponin, and this slides the tropomyosin rods away from the binding sites.

Explanation:

Contraction and relaxation of muscle cells brings about movements of the body. The contractile myofilament called sarcomeres are bounded at each end by a dense stripe called the Z - line, to which the myosin fibres are attached, and lying in the middle of the sarcomere are the actin filaments, overlapping with the myosin.

When action potential spreads from the nerve along the sarcolemma (muscle cell membrane), it penetrates deep into the muscle cell through the sarcoplasm (cytoplasm of muscle cell), and releases CALCIUM from the intracellular stores.CALCIUM triggers the binding of myosin to the actin filament next to it forming CROSS BRIDGES.

For this to occur, ACTIN BINDING SITE has to be made available. TROPOMYOSIN is a protein that winds around the chains of the actin filament and covers the myosin-binding sites to prevent actin from binding to myosin. The first step in the process of contraction is for calcium ions to bind to troponin so that tropomyosin can slide away from the binding sites on the actin strands.

Which body systems work together to move your hand when you touch something hot?

Answers

Answer:

The nervous system takes in information through our senses, processes the information and triggers reactions, such as making your muscles move or causing you to feel pain. For example, if you touch a hot plate, you reflexively pull back your hand and your nerves simultaneously send pain signals to your brain

What are the possible benefits of hybridization?

Answers

Answer: Advantages of hybridization are passing down favorable traits and prolonging the survival of a threatened or endangered species.

Hope this helps! ^^

Answer:

Advantages of hybridization include passing along favorable traits and prolonging the survival of a threatened or endangered species, but a disadvantage is that hybrid animals have more difficulty finding mates and successfully breeding. Hybridization occurs naturally and through human initiation.

Describe the structure of the conjugated protein
haemoglobin, with reference to the levels of protein
structure.

Answers

Answer: Answer below, hope this helps! :D

Explanation:

A conjugated protein is a protein that functions in interaction with other (non-polypeptide) chemical groups attached by covalent bonding or weak interactions. ... The non-amino part of a conjugated protein is usually called its prosthetic group. Most prosthetic groups are formed from vitamins. Hemoglobin is a protein having a globular structure. Based on its structural properties, hemoglobin can be divided into two parts; a protein part and a heme group. The structure of the protein part can be studied at four levels; primary structure, secondary structure, tertiary structure, and quaternary structure.

uses of crush in the farm​

Answers

Answer:

ok i dont understand what that is

Explanation:

Answer: The overall purpose of a crush is to hold an animal still to minimise the risk of injury to both the animal and the operator while work on the animal is performed.

What is seed dispersal? Name some agents of seed dispersal​

Answers

Answer:

The Process by which seeds spread over a wide area is known as seed dispersal..

some agents

Air

water

animals

etc..

Answer:

Seed dispersal is the movement, spread or transport of seeds away from the parent plant.

The most common methods are :

wind, water, animals, explosion and fire.

I need someone to do a very big task for me in biology..I will give brainlist. The teask i need is the first one in my profile. Thankyou

Answers

Answer:

Explanation:

i'll try

What process increases genetic variation

A. Mitosis
B. Asexual Reproduction
C. Codominance
D. Crossing- Over

Answers

Answer:

Crossing Over

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Tell whether x and y are in a proportional relationship. If so, find the unit rate. Let y be the temperature x hours after midnight. The temperature is 60F at midnight and decreases 2F every 1/2 hour A customer who came one day to his little bookstore in Philadelphia, not being satisfied with the price demanded by the clerk for the book he wished to purchase, asked for the owner. "Mr. Franklin is very busy just now in the press room," replied the clerk. The man, however, who had already spent an hour aimlessly turning over books, insisted on seeing him. In answer to the clerk's summons, Mr. Franklin hurried out from the newspaper establishment at the back of the store. What is the lowest price vou can take for this book sir asked the leisurely customer.What is a central idea of the selection?A. Books take time to select. B. Time is extremely valuable. C. Clerks are not always right.D. Everything costs too much money. Read the first two steps in writing a rebuttal.1. Acknowledge the counterclaim a reader might have.2. Provide a reason the counterclaim is weak.What is the third step in crafting an effective rebuttal?Restate the original claim and one piece of supporting evidence.Present evidence to support this reason and refute the counterclaim.Explain that the counterclaim is incorrect and restate the claim.Provide a list of other authors who agree with the claim and its reasons. In a command economy, which group is most responsible for producing thegoods people in society need?A. International corporationsB. Private businessC. Government agenciesD. Family members Please help me again!!!!!!!! In the story to my old master how does the organization of the selection contribute to the authors purpose? Which of the following is not equivalent to x-y+z? y-X+Y-Z x+Z- y z+x-y Z- y + x ______________ used a whole-tone scale to create an exotic sound.Wassily KandinskyClaude DebussyEdvard MunchIgor Stravinsky hey guys I need this. it's due tomorrow. and please show step by step because I am willing to give brainly what are some of the typical characteristics of graphic art works 19. Find the equation of the line that contains the given points. Write the equation in slope-intercept form, if possible.(-5,-5) and (1,7)Please solve step by step 4 x 6 + 29 divided by 5 - 4 how does paragraph 4 contribute to the development of the themeof the story?Mrs. Pynchum kept the poor-farm, and Gobaly was towns poor. The boys sometimes called him that, when he went to coast on Three-Pine Hill or to see the skating on the mill-pond; and sometimes, too, they made fun of his clothes. But it was only the boys who were a great deal bigger than he who dared to make fun of Gobaly, and some of them even ran when he doubled up his fists. But Methuselah!5 I dont know what would have become of Methuselah if he had not had Gobaly to defend him. For he was a delicate little fellow; spindlin and good for nothin, Mrs. Pynchum called him; and he had come to her in a basket in other words, Methuselah was a foundling. Mrs. Pynchum didnt think much of children who came from nobody knew where. It didnt seem to belong to Poplarville to support him, since he didnt belong to anybody that ever lived there, and his keep and his medicine cost more than he would ever be worth, to anybody. Hellllllllllo aluachantarAnswer this I cant seem how Whats 2+2 then -3? b) Draw the graph of y = 3x - 1on the grid. Is this good enought to record and edit in 4k UHD? (Ultra High Definition) If 10.88 moles of NH3 were produced, how many moles of N2 would berequired? What is the molecular formula of a compound that is 51.02 % carbon, 13.80 % hydrogen, and 35.18 %oxygen? The molecular mass is 88.0 g/mol. what is the y-intercept of the following equation Find the value of x in the triangle shown below 9 12