What is DNA primarily composed of?

DNA is primarily composed of deoxyribonucleic acid, which is reflected in its name. This molecule consists of a long chain of nucleotides, each containing three components: a phosphate group, a deoxyribose sugar, and a nitrogenous base. The structure of DNA forms a double helix, where the sequence of nitrogenous bases encodes genetic information.

The term "deoxyribonucleic acid" specifically indicates that the sugar in the backbone of DNA is deoxyribose, which distinguishes it from RNA (ribonucleic acid), where the sugar is ribose. Thus, identifying DNA by its full name encapsulates its unique structure and function in storing and transmitting genetic information.

The other choices refer to different entities or components that do not accurately describe the primary composition of DNA. Amino acids and proteins are crucial to biological processes, particularly in the synthesis of proteins through translation, but they are not components of DNA itself. Similarly, carbohydrates and lipids serve vital roles in biological systems but are separate macromolecules that do not comprise DNA.