The correct answer is: D. All of the above
Thymine, adenine, and guanine are found in DNA nucleotides, but uracil is not. Uracil is found in RNA nucleotides instead.
DNA is made up of two strands of nucleotides that are twisted together in a double helix shape. Each nucleotide consists of a sugar, a phosphate group, and a nitrogenous base. The four nitrogenous bases in DNA are adenine (A), thymine (T), guanine (G), and cytosine (C). The bases are complementary to each other, meaning that A always pairs with T and C always pairs with G. This complementary base pairing is what holds the DNA double helix together.
RNA is also made up of nucleotides, but the sugar in RNA is ribose instead of deoxyribose. The four nitrogenous bases in RNA are adenine (A), guanine (G), cytosine (C), and uracil (U). Uracil is complementary to adenine, just like thymine is. However, thymine is not found in RNA because it would not be able to pair with adenine.
The following table summarizes the differences between DNA and RNA:
| Nucleic acid | Sugar | Nitrogenous bases |
| ———– | —– | ———– |
| DNA | Deoxyribose | Adenine (A), thymine (T), guanine (G), cytosine (C) |
| RNA | Ribose | Adenine (A), guanine (G), cytosine (C), uracil (U) |