What is defined as a sequence of bases on DNA that codes for proteins?

A sequence of bases on DNA that codes for proteins is defined as a gene. Genes are the fundamental units of heredity and contain the specific instructions for building proteins, which perform various functions in the body. Each gene has a particular location on a chromosome and can vary in length, with some genes containing several hundred base pairs, while others may have thousands.

A chromosome refers to a structure that houses many genes and is composed of DNA and proteins. An allele is a variant form of a gene that may produce different traits. The genome encompasses the complete set of genetic material, including all of an organism's chromosomes and genes. Thus, the gene is the most specific term for the sequence of DNA that directly encodes for proteins, making it the correct choice in this context.