In RNA, which base would pair with thymine if thymine were present?

• A. Guanine
• B. Cytosine
• C. Uracil
• D. Adenine

Answer: (D)

Verified step by step guidance

1. Recall the base pairing rules in DNA and RNA. In DNA, adenine (A) pairs with thymine (T), and guanine (G) pairs with cytosine (C).
2. Understand that RNA normally contains uracil (U) instead of thymine (T). In RNA, adenine pairs with uracil.
3. Consider the hypothetical scenario where thymine is present in RNA. Since thymine pairs with adenine in DNA, the same pairing logic would apply.
4. Therefore, if thymine were present in RNA, it would pair with adenine, just as it does in DNA.
5. Summarize that the complementary base to thymine, whether in DNA or hypothetically in RNA, is adenine.