Which category of genetic information serves as a unit of heredity?

A gene is the correct answer because it serves as the fundamental unit of heredity. Genes are segments of DNA that carry the instructions for making proteins, which ultimately determine the traits and characteristics of an organism. Each gene is responsible for a specific function or trait, such as eye color, hair texture, or the ability to metabolize certain substances.

Chromosomes are structures within cells that contain many genes, but they are not the basic unit of heredity themselves. Instead, they serve as the container that organizes and carries genes. Proteins, while essential for various functions in the body and made based on gene instructions, do not themselves carry hereditary information. Amino acids are the building blocks of proteins, but they do not contain genetic information either. Thus, while all the other options are related to genetics, only a gene directly serves as a unit of heredity.