Final answer:
The subunits of DNA are nucleotides, composed of a phosphate group, a pentose sugar, and a nitrogen-containing base. These nucleotides connect to create the structure of DNA and play a vital role in genetics and protein synthesis.
Step-by-step explanation:
The subunits of DNA are nucleotides. This means that the correct answer to the multiple-choice question is a. Nucleotides. Nucleotides themselves are made up of three components: a phosphate group, a pentose sugar, and a nitrogen-containing base.
These subunits link together in long chains through the sugar and phosphate to form the backbone of DNA with the nitrogenous bases pairing in the center, creating the structure known for its double helix shape. Nucleotides are fundamental to the structure of nucleic acids, like DNA and RNA, and play a critical role in genetics as they code for the synthesis of proteins and are inherited by offspring from their parents.
Expanding on the hierarchy of DNA structure in relation to the review question, the correct order from smallest to largest is: C. nitrogen base, D. nucleotide, E. codon, B. gene, A. chromosome.