Explain why genetic diversity is necessary in order for natural selection to occur

It is significant because, this is where the stronger and more affinated genes are conceived, thus survive.

Genetiic variation is simply the different variety of genetic make up and what is called alleles. Alleles are similar to a code for the body which determines such things as hair color, eye color, height, and other factors.

Genetic variation is therefore the variation between genes and alleles, within a small or large group of people. A small group of people would for example be a family. A large group of people would for example be the population of a certain geographic region such as a country.