What is the structure of DNA?

The structure of DNA is best described as a double helix. This means it consists of two long strands of nucleotides that wind around each other, resembling a twisted ladder. Each strand is made up of a sequence of nucleotides, which are composed of a sugar, a phosphate group, and a nitrogenous base. The two strands are held together by complementary base pairing between the nitrogenous bases, with adenine pairing with thymine and cytosine pairing with guanine.

This double helical structure is crucial for DNA's functions, including the replication of genetic information and the encoding of proteins. The stability and flexibility of the double helix allow DNA to store and transmit genetic information efficiently. Other options, such as a single strand, triple helix, or linear strand, do not accurately capture the true structure of DNA as we understand it in molecular biology.