Question

DNA strands are made up of phosphate groups, pentose sugar and four types of ______ bases.

Answer 1

DNA strands are made up of phosphate groups, pentose sugar and four types of nitrogen bases.

Explanation:

The four types of nitrogenous bases present in DNA are adenine (A), thymine (T), guanine (G), and cytosine (C). These bases attach to the pentose sugar (deoxyribose) and pair up predictably across the two strands through hydrogen bonds to form the rungs of the double helix. Together with the sugar and phosphate groups, they form the structural units known as nucleotides that store genetic instructions.