Approximately twenty-five elements occur naturally on earth. Remaining elements either have to be synthesized or obtained through chemical reactions.
Answer:
e. is under purifying selection
Explanation:
Purifying selection removes deleterious alleles that can arise through
random mutations
.
Mutations may or may not have consequences at the level of genetic expression depending on whether those mutations are synonymous or nonsynonymous. Synonymous mutations do not generate changes in the protein to be encoded while non-synonymous ones do.
Important genes for the development of the organism - such as those involved in the neural development- are very likely to be under purifying selection, eliminating individuals with deleterious alleles since those alleles (product of non-synonymous substitutions) do not allow the individuals to survive.
