Answer:
The correct answer will be- nitrogenous bases (purines and pyrimidines)
Step-by-step explanation:
Deoxyribose nucleic acid or DNA is the genetic material of the organism which exists in the organisms as a ladder-shaped helical model.
The helical structure is formed by the two strands of DNA in which each strand of DNA is composed of monomer units called nucleotide.
Each nucleotide is made of a five-carbon sugar (Deoxyribose), a phosphate group and two different classes of nitrogenous bases mainly purine and pyrimidine. The purine bases are adenine and guanine whereas pyrimidine is cytosine and thymine.
Thus, nitrogenous bases (purines and pyrimidines) is the correct answer.