What are the five nucleotides?

• A. A, C, G
• B. T, U
• C. X, Y, Z
• D. G, C, A, T, U

Answer: (D)

Five nucleotides are the five nitrogenous bases used in genetics: adenine, cytosine, guanine, thymine, and uracil. DNA uses thymine, while RNA uses uracil, and when you consider both molecules together, these five bases cover all possibilities: A, C, G, T, and U. The choice that lists all five—G, C, A, T, U—is the correct one because it includes every base found in DNA and RNA. The other options miss bases or include symbols that aren’t nucleotides.