Which statement correctly describes a key way RNA differs from DNA?

• A. RNA contains deoxyribose sugar, while DNA contains ribose sugar.
• B. RNA is typically single-stranded and contains uracil (U) instead of thymine (T).
• C. RNA is typically double-stranded and contains thymine (T) instead of uracil (U).
• D. RNA is more chemically stable than DNA because RNA lacks a 2′ hydroxyl group.

Answer: (B)

Verified step by step guidance

1. Identify the structural components of DNA and RNA, focusing on the sugar and nitrogenous bases present in each molecule.
2. Recall that DNA contains deoxyribose sugar, which lacks a hydroxyl group at the 2' carbon, while RNA contains ribose sugar, which has a hydroxyl group at the 2' carbon.
3. Understand the difference in nitrogenous bases: DNA contains thymine (T), whereas RNA contains uracil (U) instead of thymine.
4. Consider the typical strand structure: DNA is usually double-stranded forming a double helix, while RNA is usually single-stranded.
5. Evaluate the chemical stability: DNA is generally more stable than RNA because the 2' hydroxyl group in RNA makes it more reactive and less stable chemically.