In RNA, which nitrogenous base pairs (forms hydrogen bonds) with adenine (A) during complementary base pairing?

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

Answer: (B)

Verified step by step guidance

1. Recall that in DNA, adenine (A) pairs with thymine (T) through hydrogen bonding during complementary base pairing.
2. Understand that RNA differs from DNA in that it contains uracil (U) instead of thymine (T).
3. Recognize that during RNA complementary base pairing, adenine (A) pairs with uracil (U) instead of thymine.
4. Note that cytosine (C) pairs with guanine (G) in both DNA and RNA, so they are not the correct partners for adenine.
5. Conclude that the nitrogenous base that pairs with adenine (A) in RNA is uracil (U).