I NEED HELP ASAP! Which of the following is true of variation? Select one:
a.
It is necessary for natural selection.
b.
It exists in almost all populations.
c.
It is caused by mutations and sexual reproduction.
d.
All of the choices are correct.

During a fierce storm a large number of tall trees on an island are uprooted by the wind and die. most of the trees on the island are now short trees and produce seeds that grow into short trees. what concept is shown in this example? question 5 options: natural selection artificial selection genetic engineering gene splicing