Complementary base pairing is considered which level of structure?

A. Secondary

B. Tertiary

C. Quaternary

D. Primary

The correct option is: A. Secondary

Explanation:

The structure of the nucleic acids i. e DNA and RNA, is divided into the following levels: primary, secondary, tertiary and quaternary.

The secondary structure of the nucleic acid is responsible for the shape of that nucleic acid. It is characterized by complementary base-pairing between the two polynucleotide strands, which wraps around each other to form a double helix. The secondary structure is stabilized by hydrogen bonding.