The answer is stabilizing selection.
<span>Sickle-cell anemia is a recessive disorder caused by the presence of two recessive alleles "s", so genotype is "ss". This disorder is characterized by sickle hemoglobin. In an area with malaria, heterozygous individuals "Ss" (with one dominant allele and one recessive allele) have an advantage. These individuals will have both normal and sickle hemoglobin. But pathogen that causes malaria affect only normal hemoglobin, so heterozygous individuals will have half of the hemoglobin resistant to the pathogen and those individuals are resistant to malaria.</span>
Stabilizing selection favors heterozygotes Ss, disruptive selection favors dominant (SS) and recessive (ss) homozygotes, while directional selection favors dominant (SS) or recessive (ss) homozygote. Since in this example, people with genotype Ss (heterozygotes) are in advantage, then this is an example of stabilizing selection.
An hypothesis is a possible explanation for a set of observations or answer to a scientific question. A supposition or proposed explanation made on the
basis of limited evidence as a starting point for further
investigation.
And practically, an hypothesis is used as the basis for further experiments, where the hypothesis is rigorously tested under varying conditions. The hypothesis that is tested and modified under different conditions may become a general
theory
.The hypothesis that has the least number of variables sufficient to explain the phenomenon is preferred.
Not true, certain chemical transmitters stimulate certain receptors
Answer:
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Explanation:
A mutation is a change in a DNA sequence. Mutations can result from DNA copying mistakes made during cell division, exposure to ionizing radiation, exposure to chemicals called mutagens, or infection by viruses.
