Which of the following is not a constituent of DNA?

Uracil is not a constituent of DNA. DNA (deoxyribonucleic acid) is made up of four basic building blocks, called nucleotides, which consist of a phosphate group, a sugar molecule called deoxyribose, and a nitrogenous base. The four nitrogenous bases found in DNA are adenine (A), guanine (G), cytosine (C), and thymine (T). Uracil is a nitrogenous base that is found in RNA (ribonucleic acid), which is a related molecule to DNA but has a slightly different structure. RNA also contains a phosphate group and a sugar molecule (ribose) but instead of thymine, it contains uracil as one of its four nitrogenous bases.