After which event has evolution occurred?
a. a new predator comes into an environment
b. an individual is born with 6 fingers on one hand instead of 5
c. an animals white winter coat is replaced by a darker coat in the spring
d. an allele frequency in a population changes over time

explanation:

i think that d. wind is the answer.   i missed the question when i answered a. currents.

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.