Which of the following best defines a gene pool

Explanation:

here are the choices:

A. the sum of all genetic traits in a population’s individuals at a given time

B. any movement of genes from one population to another

C. any movement of organisms from one environment to another

D. the random change in the frequency of an allele in a population

when atoms of different types of elements join together, they make molecules called compounds. water consists of compound molecules made up of 2 hydrogen atoms and 1 oxygen atom. this is why it's called h2o. water will always have 2 times the number of hydrogen atoms as oxygen atoms.