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

5. What would our planet be like without plants?​

Answers

Answer:

we would die plants give us oxgen fruits and vegtebales  . trees for example we need wood and there leaf to make  doors and paper

Explanation:

If the planet didn’t have plants, we would be lacking in fruits and vegetables. We probably wouldn’t be too healthy. We would also be lacking in oxygen as things like trees give us oxygen. The trees also enable people to make doors and even paper. If we didn’t have trees, we probably would struggle with getting privacy since (doors) allow us to keep a boundary from people you wouldn’t want to go in (say like in your bedroom or home even.)

I hope this makes some sense

A male and a female are both heterozygous for a particular trait. Which of the following represents the expected ratio of dominant to recessive phenotypes in the offspring?

Answers

The given question is incomplete as it lack the options, however, answer can be given by the provided information.

Answer:

The correct answer is - 3:1 ratio.

Explanation:

In the question it is given that both male and female both are heterozygous for the trait, let assume dominant allele A and recessive allele a so the the gene for the both male and female is Aa.

Punnett square for the cross between both:

gametes: A, a and A, a.

A a

A AA Aa

a Aa aa

here two out of four are heterozygous dominant and one is dominant and one is recessive.

thus, 3 out of 4 are dominant and one out 4 are recessive.

thus, the answer is 3:1 ratio

Answer:

For the 4th time I need more points and its C

Explanation:

1.How does Nitrogen cycle through the enviroment?
2. Trace the steps that carbon cycles from plants,animal,and enviorment?​

Answers

Answer: 1. The nitrogen cycle is a biogeochemical cycle.

2. The carbon cycle is a biogeochemical cycle.

Explanation:

1. The nitrogen cycle can be defined as the biogeochemical cycle in which the atmospheric nitrogen is utilized by the plants which is fixed by the soil bacteria. The nitrogen becomes the part of the biosphere as plants utilize it as an important development mineral. The nitrogen cycle involves the nitrogen fixation in which plants fix nitrogen by the help of bacteria into ammonia, nitrification in which the ammonia is converted into nitrite, nitrogen assimilation in which the plants assimilate and utilize the nitrogen for their growth and development, and denitrification involves the reduction of nitrite into atmospheric nitrogen. The conversion of nitrogen is carried out via physical and biological processes.

2. The carbon cycle involves the atmospheric carbon dioxide being circulated in plants as they utilize it for photosynthesis. The carbon dioxide is fixed by the plants in the form of carbohydrate which is consumed by the animals and on decomposition of plants and animals dead matter release carbon dioxide gas to the atmosphere. This allows the recycling of the carbon dioxide gas in the environment.

Examine equations A and B below. Then answer the questions.
(A) 2H2 + O2 ® 2H2O (B) H2CO3 - H + HCO3


20. Which equation represents the formation of water?

21. Which equation represents the formation of an acid solution?


22. How many atoms of oxygen (O) are on both sides of equation

23. How many atoms of hydrogen (H) are on both sides of equation

24. How many atoms of hydrogen (H) are on both sides of equation

25. In which equation are carbonic acid molecules broken apart into
hydrogen ions and bicarbonate ions?

Answers

Answer: 20. A 21. B 22. A=2, B=3 23. A=4, B=3 25. B

Explanation: A has H2O (water). B has a hydrogen ion, so acidic.

In B H2CO3 is carbonic acid

The loss of hydrogen atoms leads to the formation of acids and the hydroxide forms bases. Equation A represents the formation of water, and equation B shows the acidic solution.

What is a chemical reaction?

Chemical reactions are said to be involved in producing products from the reactants that undergo chemical changes. Water is formed by reacting the four hydrogens and one oxygen molecule as:

2H₂ + O₂ → 2H₂O

Equation B represents the formation of the acid as hydrogen ions are released along the product. The proton donation (hydrogen ion) is the characteristic property of the acids.

There are 2 oxygen atoms in equation A, and 3 atoms of oxygen in equation B.

There are 4 hydrogen atoms in equation A and 2 atoms of hydrogen in equation B.

In equation B, carbonic acid breaks to form hydrogen ions and bicarbonate ions as:

H₂CO₃ → H⁺ + HCO₃

Here, carbonic acid dissociates a proton that makes the solution acidic.

Therefore, the first equation represents the formation of water by oxygen and hydrogen atoms.

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PLEASE HELP I NEED TO FINISH BEFORE TODAY!!!!!!!!!!!A city sits in the middle of a broad, flat plateau that is 800 meters above sea level.
The plateau is surrounded by lower land on all sides. Which power plant would have
the HARDEST time generating power if it were built on this plateau?

Answers

Answer:

i believe it would be hydroeletric because it is above sea level and wouldnt get water.

State the " Central Dogma of Biology"​

Answers

Answer:

the central dogma of biology explores how genetic information in our cells goes from DNA to RNA to proteins.

Answer:

The central dogma states that the pattern of information that occurs most frequently in our cells is: From existing DNA to make new DNA (DNA replication?) From DNA to make new RNA (transcription) From RNA to make new proteins (translation).

Explanation:

Hope it helps

FOLLOW MY ACCOUNT PLS PLS

The mass of a cylinder of beetroot was 2.5 g. If its final
mass was 2.7 g, what was the
increase in mass in per cent?

Answers

Answer: The percent increase in the mass of cylinder of beetroot is 8%.

Explanation:

To calculate the percent increase in the mass of cylinder, we use the equation:

[tex]\%\text{ increase in mass}=\frac{\text{Final mass - Initial mass}}{\text{Initial mass}}\times 100[/tex]

We are given:

Final mass of the cylinder = 2.7 g

Initial mass of the cylinder = 2.5 g

Putting values in above equation, we get:

[tex]\%\text{ increase in mass}=\frac{2.7-2.5}{2.5}\times 100\\\\\%\text{ increase in mass}=8\%[/tex]

Hence, the percent increase in the mass of cylinder of beetroot is 8%.

Which activity can be accomplished using the genetic code?
O A polypeptide can be made into mRNA
. DNA can be made into mRNA
O RNA can be copied before mitosis.
O mRNA can be made into tRNA

Answers

Answer:

DNA can be made into mRNA

Explanation:

And, what else it literally says CHECK ALL THAT APPLY like....

Answers

Answer:

i dont understand??????

Explanation:

Answer:

What??

Explanation:

This makes no sense to me...


1 The blank
is the sun and
all of the planets and other bodies that travel
around it.

Answers

Answer:

solar system

Explanation:

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

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.

Asexual reproduction can be advantageous for species that colonize new areas.

A. True

B. False

Answers

Answer:

True

Explanation:

It can rapidly increase if the environment is good for them

In 1956 Tijo and Levan first successfully counted human chromosomes. The reason it would have taken so manyyears to have done so would have included all but which of the following?

a. Watson and Crick's structure of DNA was not done until 1953.
b. Chromosomes were piled up on top of one another in the nucleus.
c. Chromosomes were not distinguishable during interphase.
d. A method had not yet been devised to halt mitosis at metaphase.

Answers

Answer:

A

Explanation:

The correct answer would be that Watson and Crick's structure of DNA was not done until 1953.

The fact that chromosomes are condensed together in the nucleus, are not distinguishable during interphase, and a method had not yet been devised to halt mitosis at metaphase could have plausibly delayed the successful counting of human chromosomes.

On the other hand, the discovery of the structure of the DNA could not have delayed the study of chromosomes because the DNA structure has no bearing on the karyotyping of chromosomes.

The chromosomes of organisms are best studied using a relevant microscope during metaphase when they would have fully decondensed and align at the equator of the cell or the metaphase plate. At the interphase phase of the cell cycle, chromosomes are full condensed under the view of the microscope.

The correct option is, therefore, A.

Which is a characteristic of diatoms?

Answers

Diatoms have two distinct shapes: a few (centric diatoms) are radially symmetric, while most (pennate diatoms) are broadly bilaterally symmetric. A unique feature of diatom anatomy is that they are surrounded by a cell wall made of silica (hydrated silicon dioxide), called a frustule.

Diatoms have two distinct shapes: a few (centric diatoms) are radially symmetric, while most (pennate diatoms) are broadly bilaterally symmetric.

What are Diatoms?

Any member of the vast group of several genera of microalgae that can be found in the world's oceans, streams, and soils is referred to as a diatom.

Diatoms can photosynthesize, which allows them to change the dissolved carbon dioxide in the water into oxygen.

For higher-ranking organisms in the food chain, like invertebrates and tiny fish, they serve as a major source of food. In the energy and nutrition cycles of water resources, diatoms can also be vital players.

Diatoms can be divided into two shapes: pennate diatoms, which make up the majority, are broadly bilaterally symmetric, and central diatoms, which make up the minority.

Thus, these are the characteristics of diatoms.

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What is the area of a square if the perimeter is 40
units?

Answers

Answer:

this is the ans

Explanation:

first we have to write formula of area of square is

[tex]l {}^{2} [/tex]

Plz answer as quick as possible

Answers

Answer:

celluar wall

Explanation:

im prob wrong btw

How many layers are in a typical landfill liner between the clay in the ground
and the solid waste?
Select one:
a. 2
b. 3
c. 4
d. 10

Answers

I think the answer is C

:):):):):)

explain the process of DNA extraction and gel electrophoresis

Answers

Answer:

The process of that same framework in question is defined below.

Explanation:

The DNA was indeed prepared by mixing with either a dye as well as a radioisotope which enables the gel to have been recognized. The specific filaments would then be differentiated from one another DNA electrophoresis. The procedure occurs with the injection including its completely separate genetic code into boreholes that have already been reduced either at the final moment including its gel pavement.

Why does the air at higher pressure move downward?

Answers

He already gave the answer

which type of cell does the strainer best model?

Answers

Answer:

D

Sieve tube element, because it has openings that allow materials to pass through its end walls.

Answer:

D. Sieve tube element, because it has openings that allow minerals to pass through its end walls

Explanation:

I'm taking the test right now, I hope this helps

5. The double helix model of DNA explained Chargaff's rules
because
A. adenine could hydrogen-bond with thymine and
guanine could hydrogen-bond with cytosine to hold the
helix together.
B. a helix repeats itself many times over, so the four bases
in DNA can repeat themselves many times.
C. adenine and thymine are found in one strand of the
double helix and guanine and cytosine are found in the
other strand.
OD. adenine could change places with thymine while
munninn anuld chanannhan with

Answers

Answer:A adenine could hydrogen-bond with thymine and guanine could hydrogen bond with cytosine to hold the helix together

Explanation:

The double helix model of DNA explained Chargaff's rules because adenine could hydrogen-bond with thymine and guanine could hydrogen-bond with cytosine to hold the helix together. The correct option is A.

What is Chargaff's rule?

According to Chargaff's criteria, guanine and cytosine should be equal in amount in the DNA of every species and organism, and adenine and thymine should be equal in amount.

Additionally, the purine and pyrimidine bases should be in a 1:1 stoichiometric ratio.

The ratio of the several nitrogenous bases present inside the DNA molecule is described. It assists in figuring out the makeup and structure of DNA in various species.

Because adenine could hydrogen bond with thymine and guanine could hydrogen bond with cytosine to maintain the helix together, the double helix model of DNA provided an explanation for Chargaff's rules.

Thus, the correct option is A.

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What heat transfer method gives plants the energy they need for photosynthesis to take place?
Conduction
Convection
Radiation
Glucose

Answers

Answer: radiation

Explanation:

Answer:

Radiation

Explanation:

plants need radiation to produce sunlight in order for them to carry out photosynthesis

the type needed is photosynthetically active radiation (PAR)

Cells in the body needs what for energy

Answers

Answer:

Mostly glucose

Explanation:

Answer:

Different Cell Types Require Different Fuel Molecules. Red blood cells rely on glucose for energy and convert glucose to lactate. The brain uses glucose and ketone bodies for energy. Muscle cells use fatty acids, glucose, and amino acids as energy sources.

Traits are controlled by
hybrids
alleles
purebreds
genetics

Answers

Answer:

Genetics

Explanation:

A trait is a specific characteristic of an organism. Traits can be determined by genes or the environment, or more commonly by interactions between them. The genetic contribution to a trait is called the genotype. The outward expression of the genotype is called the phenotype.

Use the graph and the table above to complete the table by estimating the amount of energy transferred near location B.

A.
1600 kilojoules

B.
300 kilojoules

C.
800 kilojoules

D.
400 kilojoules

E.
3200 kilojoules

Answers

The answr is A
Step explain
The answer is A 1600 kilojoules

ideas on a science experiment that has to do with marine science?​

Answers

Answer:

SALT WATER DENSITY

LAYERS OF THE OCEAN

SHARK BUOYANCY

HOW WHALES STAY WARM

TIDE POOL

WATER/SHORELINE EROSION

OCEAN BOTTLE

CORNMEAL CURRENTS

DEEP-WATER CURRENTS

PENGUIN CAMO

Explanation:

How can you recycle your trash?

Answers

Answer:

when people recycle they really just need to pickup after themselves

Answer:

cleaning up after yourself, learning the proper way to decompose of things, throw trash out and recycle plastic by picking it up, clean up cans, and tell others to help out!

Feeding problems may develop during the preschool years partially because of:_______

a. decreased appetite associated with decreased growth rate.
b. increased appetite associated with increased growth rate.
c. increased metabolic rate.
d. increased need for finger foods.

Answers

Answer:

The correct option is A.

decreased appetite associated with decreased growth rate

Explanation:

Feeding problems may develop in preschool age because of decreased appetite associated with decreased growth rate and this is because at the preschool age, there is no rapid growth, the growth rate is reduced which is as a result of decreased appetite for food. We all know that food supply the body with energy and necessary nutrients for growth. When there is decreased appetite enough food needed for growth will not be consumed , hence decrease growth rate.

How does the double helix structure of DNA support its role in encoding the genome?
1)The sugar-phosphate backbone provides a template for DNA replication
2)tRNA pairing with the template strand creates proteins encoded by the genome
3)Complementary base-pairing creates a very stable structure
4)Complimentary base pairing allows for easy editing of both strands of DNA

Answers

Answer: Complementary base- pairing creates a very stable structure

Explanation:

The double helix structure of deoxyribonucleic acid (DNA) support its role in encoding a genome because the: 3. Complementary base-pairing creates a very stable structure.

A double helix can be defined as the spiral configuration of the deoxyribonucleic acid (DNA) molecule.

In Biology, a double helix is typically used to describe the molecular structure of a double-stranded deoxyribonucleic acid (DNA) molecule, which comprises two (2) linear strands that are complimentary and run opposite to each other and twist together (anti-parallel).

Hence, the complementary base-pairing in a double-stranded deoxyribonucleic acid (DNA) or double helix structure of deoxyribonucleic acid (DNA) helps to create a very stable structure, which in turn makes it possible to encode a genome.

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