RNA differs from DNA in that RNA typically:

• A. Contains the bases adenine, guanine, cytosine, and thymine
• B. Contains ribose sugar and uses uracil instead of thymine
• C. Contains deoxyribose sugar and uses thymine instead of uracil
• D. Is usually double-stranded and lacks complementary base pairing

Answer: (B)

Verified step by step guidance

1. Identify the key structural components of DNA and RNA, focusing on their sugar molecules and nitrogenous bases.
2. Recall that DNA contains deoxyribose sugar, while RNA contains ribose sugar, which has an extra oxygen atom compared to deoxyribose.
3. Understand that DNA uses the bases adenine (A), guanine (G), cytosine (C), and thymine (T), whereas RNA uses adenine, guanine, cytosine, and uracil (U) instead of thymine.
4. Note the typical strand structure: DNA is usually double-stranded with complementary base pairing, while RNA is usually single-stranded.
5. Combine these facts to determine that RNA differs from DNA primarily by containing ribose sugar and using uracil instead of thymine.