Answer:
In 1953, Watson and Crick determined the double-helix composition of DNA, that is, the molecule comprising human genes. They found that the composition of DNA was a spiral of two strands of DNA or a double-helix polymer, each comprising a lengthened monomer chain, that is, the nucleotides wrapped around each other.
The DNA, that is, a nucleic acid formed of nucleotides combined into chains or long strands with the help of covalent bonds. The nitrogenous bases present in the DNA are guanine, adenine, thymine, and cytosine.