Could someone please check this definition and tell me if it's good or if it's too much (whatever)

Question

Variation=the existence of differences between the individuals in a population. It can be described as continuous or discrete. Examples of discrete variation are gender and eye colour which often arises when the character is controlled by a small number of alleles. An Example of continuous variation is height. Continous variation often arises when a large number of independent factors influence the character. Only variations due to genetic constitutions can be inherited.