Which nucleotide base indicates that a nucleic acid is RNA rather than DNA?

• A. Thymine (T)
• B. Adenine (A)
• C. Guanine (G)
• D. Uracil (U)

Answer: (D)

Verified step by step guidance

1. Understand the basic components of nucleic acids: DNA and RNA are both made up of nucleotides, which include a sugar, a phosphate group, and a nitrogenous base.
2. Recall the four nitrogenous bases found in DNA: Adenine (A), Thymine (T), Cytosine (C), and Guanine (G).
3. Recall the four nitrogenous bases found in RNA: Adenine (A), Uracil (U), Cytosine (C), and Guanine (G).
4. Note the key difference between DNA and RNA bases: DNA contains Thymine (T), whereas RNA contains Uracil (U) instead of Thymine.
5. Therefore, the presence of Uracil (U) in a nucleic acid sequence indicates that the molecule is RNA rather than DNA.