DNA (deoxyribonucleic acid) is a type of macromolecule known as a nucleic acid. It is composed of long chains (polymers) of nucleotides, which are its monomer units. Each nucleotide consists of a phosphate group, a sugar called deoxyribose, and a nitrogenous base (adenine, thymine, cytosine, or guanine)

. DNA is one of the four major types of biological macromolecules essential for life, alongside proteins, lipids, and carbohydrates. It carries the genetic instructions necessary for the development, functioning, growth, and reproduction of all living organisms and many viruses

. Structurally, DNA is a double-stranded polymer forming a double helix, with the two strands held together by base pairing between complementary nucleotides (A pairs with T, and C pairs with G)

. In summary, DNA is a nucleic acid macromolecule that stores and transmits genetic information in living organisms