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3 years ago

Provide a summary of Professor Steve Jones’ findings concerning how Natural Selection may be working today in humans.

Biology

1 answer:

lesya [120]3 years ago

7 0

Answer:

John Stephen Jones states that in evolution it is necessary to have into account three factors: natural selection, mutation, and random variation.

Explanation:

These three mechanisms influence evolution and they are responsible for generating phenotypic diversity that is observed in humans.

I recommend to read his article (chapter book):

Jones, JS. (2012). Is Human Evolution Over?. In Evolution 2.0 (pp. 167-176). Springer, Berlin, Heidelberg.

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Which of the following statements is true?

gogolik [260]

The statement that is true is B. Dissolved minerals from rocks are deposited in the ocean. All of the other statements are not correct, they are false.

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3 years ago

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Before the forming urine flows into the distal tubule of the nephron, it is in the _____ ______ _____, where water is absorbed a

liraira [26]

Answer:

"Before the forming urine flows into the distal tubule of the nephron, it is in the loop of Henle, where water is absorbed as the fluid descends into the deep medulla of the kidney, and salts are absorbed as the fluid flows back up to the cortex of the kidney".

Explanation:

Henle´s loop is a specific section of renal tubules that forms the nephrons.

In this U-shaped region, the two parts of the contorted tubule, the distal and the proximal part, are very close to each other. In the kidney, both parts of the tubules are located in the renal cortex, while the loop of Henle is located within the renal medulla.

The proximal region of the Henle´s loop is a permeable region, unlike the proximal and distal regions of the renal tubule.

This is why it is possible the interchange of water and ions in the Henle´s loop. In the loop´s walls, cells present aquaporines in their membranes that allow passive water absorption, while they do not allow the transport of ions and urea. In this way 25% of the water that passes through the kidney might be filtered.

The ascendant side of the loop, which is narrower, the tubule wall is impermeable to water but allows the ions´reabsorption. Here, cells present sodium, potassium, and chloride channels.

Potassium sodium pump transporters are found in the basolateral zone. While in the apical area are active transporters of the 3 ions.

Due to these differences in the water and ions´absorption between the two parts of the Henle´s loop, a countercurrent multiplier effect is produced, stratifying the osmotic compounds of the medullary interstitium, being the part closest to the cortex less concentrated than the part closest to the renal papilla, which is about 4 times more concentrated in ions.

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3 years ago

What is the number of codons needed to make an amino acid

Ugo [173]

You need three codons to make an amino acid.

4 0

4 years ago

What is the name of the period from 2 to 8 weeks following fertilization during which significant growth occurs in the major org

poizon [28]

Answer:

The correct answer is embroynic stage

Explanation:

The prenatal development is divided into three stages germinal stage, embryonic stage and fetal stage. The period of two weeks after fertilization is called the germinal stage. In this stage, the zygote divided and gets implanted in the uterine wall.

The embryonic stage starts for two weeks and lasts up to 8 weeks after fertilization. At this stage, the cell mass is called embryo. In the embryonic stage, the basic brain structure, CNS, PNS are developed. All the basic organs and body parts develop in this stage except sex organs. So the right answer is the embryonic stage.

3 0

3 years ago

Tenesha is trying to draw a parallelogram and find its area using the two line segments shown.She begins by finding the missing

Temka [501]

Complete question:

Tenesha is trying to draw a parallelogram and find its area using the two line segments shown.She begins by finding the missing vertex on the graph to be point (9, 5). Then she calculates the area of the parallelogram. What errors did she make? Check all that apply.

She did not find the correct vertex; it should be at (8, 5).

She used the wrong area formula; it should be mr023-3

She used the wrong length for the base; it should be 7, like the given base.

She used a side length of the parallelogram for the height instead of a line segment perpendicular to the base; the height should be 3.

She should have found a segment for the top that was not parallel to the bottom.

Answer:

2nd and 3rd option is incorrect.

Explanation:

The parallelogram is a simple quadrilateral with two parallel pairs of sides. The opposite or reverse sides of the parallelogram are of similar duration and the reverse angles of the parallelogram are of equivalent proportion.

The square has two sets of parallel sides, four right angles, and the four sides are identical. It's even a triangle and a parallelogram.

The rhombus is known as a four-sided parallelogram.

Check attachment for graph

6 0

4 years ago

Read 2 more answers