What are the basic units of heredity found within DNA?

Genes are the basic units of heredity found within DNA. They are sequences of nucleotides that encode instructions for the synthesis of proteins or, in some cases, functional RNA molecules. Each gene contributes to a particular trait or characteristic in an organism, and these traits can be passed from parents to offspring through reproduction.

Chromosomes, while they contain many genes, are structures made of DNA and proteins that package and organize genetic material within the cell. Proteins are the products that are expressed as a result of gene activity, but they are not units of heredity themselves. Alleles are different versions of a gene that can exist at a specific location on a chromosome. While alleles contribute to variations in traits, they are not standalone units of heredity in the same way that genes are. Thus, the correct answer accurately identifies genes as the fundamental units of heredity.