The backbone of a nucleic acid strand is composed of

A) glycerol.
B) R groups.
C) nitrogenous bases.
D) alternating pentose sugars and phosphate groups.
E) alternating adenines and thymines.

Nucleic Acid

Macromolecules, including DNA and RNA, that store and transmit genetic information.

Pentose Sugars

A class of simple sugars that contain five carbon atoms, important in biological molecules like DNA and RNA.

Nitrogenous Bases

Organic molecules that make up the building blocks of nucleic acids, DNA and RNA, including adenine, guanine, cytosine, thymine (in DNA), and uracil (in RNA).