What are the definitions for gene pool and allele frequency? A. the alleles for a species, the number of times a gene appears
B. the number of alleles: genes that appear in a population
C. all the alleles that appear in a population: the number of times the alleles appear
D. all the genes that are present in a population; the number of times an allele occurs in a gene pool

Allele frequency- the percentage with which a specific allele is found in a population. Gene Pool- the sum total of all alleles present in all populations of a particular species. ... evolution involved a change in allele frequency in a population's gene pool over a number of generations.

Explanation:

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substitution is the answer in this case

the relative atomic mass of an element is the mass of one atom of that element, relative to 1/12th of the mass of a  1212c atom. to convert to an absolute mass in kg, it is necessary to multiply by  1.661×10−271.661×10−27.

the relative atomic mass is roughly equal to the number of neutrons, plus the number of protons, in the nucleus of the atom.

for elements with more than one stable isotope (different types of nucleus with different numbers of neutrons but the same number of protons), the quoted mass is usually the average mass, weighted by the relative abundance of the different isotopes.