Answer:
double helix
Step-by-step explanation:
Deoxyribonucleic acid, commonly known as DNA, consists of two long polynucleotide chains composed of four types of nucleotide subunits i.e. A, G, C, T. Each chain is called a strand. Each nucleotide is made up of a pentose sugar, phosphate group and a nitrogenous base.
DNA is a double-helical structure that contains each strand in a spiral or coiled form. This double helix structure forms when two complementary strands are held together by hydrogen bonds. The bonding occurs between the nucleotide base portions of the complementary strands e.g G-C, A-T.