Which combination correctly lists three standard ways RNA differs from DNA?

• A. RNA is usually single-stranded, contains ribose sugar, and uses uracil (U) instead of thymine (T).
• B. RNA is usually double-stranded, contains deoxyribose sugar, and uses thymine (T) instead of uracil (U).
• C. RNA is usually double-stranded, contains ribose sugar, and uses uracil (U) instead of thymine (T).
• D. RNA is usually single-stranded, contains deoxyribose sugar, and uses thymine (T) instead of uracil (U).

Answer: (A)

Verified step by step guidance

1. Identify the structural differences between RNA and DNA by focusing on three main aspects: strand structure, sugar type, and nitrogenous bases.
2. Recall that RNA is typically single-stranded, whereas DNA is double-stranded. This means RNA usually exists as a single chain of nucleotides.
3. Understand that the sugar in RNA is ribose, which has a hydroxyl group (-OH) on the 2' carbon, while DNA contains deoxyribose, which lacks this hydroxyl group.
4. Recognize that RNA uses the nitrogenous base uracil (U) instead of thymine (T), which is found in DNA. This substitution is a key difference in their nucleotide composition.
5. Combine these three characteristics to determine the correct description of RNA: single-stranded, contains ribose sugar, and uses uracil instead of thymine.