What are dna composed of?

deoxyribonucleic acid, a self-replicating material present in nearly all living organisms as the main constituent of chromosomes. It is the carrier of genetic information Thats the defination of DNA

The two DNA strands are known as polynucleotides since they are composed of simpler units called nucleotides. Each nucleotide is composed of a nitrogen-containing nucleobase-either cytosine (C), guanine (G), adenine (A), or thymine (T) - as well as a sugar called deoxyribose and a phosphate group.