How do differences in genetics contribute to variations among individuals?

A) They are responsible for the presence and expression of different traits.
B) They prevent bacteria from overtaking the immune system.
C) They work together with ghrelin to influence development.
D) They transfer electrical impulses throughout the body.

Ghrelin

A hormone produced in the stomach that stimulates appetite and signals the brain to increase food intake.

Genetics

The branch of biology that studies heredity.

Variations

Variations refer to differences or deviations in the characteristics of an organism, or in any other measured data, from those typical of the species or the norm.