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lara [203]
3 years ago
7

Question 20 of 30

Biology
1 answer:
eimsori [14]3 years ago
5 0

Answer:

A. The scientist should restart the experiment at a step prior to

contamination.

Explanation:

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A couple has three children, two without sickle cell anemia and one with sickle cell anemia. The mother has sickle cell anemia a
bezimeni [28]

Answer:

Explanation:

The sickle cell allele is recessive. Hence, in order for any child of the couple to have sickle cell anemia, such a child will have to inherit an affected allele each from the two parents. This means that both the father and the mother must have affected alleles in their genotypes. In other words, two sickle cell alleles are required for the abnormality to manifest.

Let us assume that the sickle cell allele is represented by S and the normal allele is represented by A.

Now, it is established that the mother has sickle cell anemia, her genotype would be SS. The father does not have sickle cell, his genotype can either be AA or AS.

Assuming the genotype of the father is AA:

          SS   x   AA

      AS   AS   AS   AS

<em>All the children would be normal in this case.</em>

Assuming that the genotype of the father is AS

           SS    x    AS

      AS   SS   AS   SS

<em>50% of the children would have sickle cell while the remaining 50% would be normal.</em>

<u>Therefore, in order to produce children with sickle cell, the father has to be AS, otherwise, he has to be AA.</u>

<u><em /></u>

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3 years ago
Hormones are chemical molecules produced by indoor green glands one such endocrine gland is the thyroid gland which synthesizes
Veronika [31]

Answer:

555

Explanation:

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2 years ago
What cell structure controls the flow of the water and sucrose into and out of the cell?
kolbaska11 [484]
The plasma membrane, because it's a selective permeable which means it only allows certain things in like sucrose.

7 0
3 years ago
Answering by analyzing this picture.
dsp73

Answer:

How do insects become resistant to pesticide? ... Upon exposure to insecticides, insects that do not carry the resistance genes die, thus allowing the individuals with the resistance genes to survive and reproduce, creating more resistant insects. With every generation the number of resistant insects increase.

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2 years ago
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A new microorganism has been isolated from hot springs in Yellowstone National Park. It consists of single cells, which appear t
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