Which of the following best defines the Theory of Natural Selection? *
The organisms that are genetically the best adapted tend to survive and reproduce.
The organisms that occupy the largest area always survive and reproduce.
The smallest organisms in a population are always eliminated by the biggest organisms.
Organisms that are the biggest and the strongest always survive.

The organisms that are genetically the best adapted tend to survive and reproduce

Explanation:

Say that in a blue environment, there are two types of deer, brown and blue. In this environment are some predator, doesn't really matter what predator. Because the brown deer are not adapted to the environment, they are more likely to be killed by a predator. While the blue would tend to survive and reproduce.

genetic variation can be caused by mutation (which can create entirely new alleles in a population), random mating, random fertilization, and recombination between homologous chromosomes during meiosis (which reshuffles alleles within an organism's offspring).

the areas around the equator