RNA differs from DNA in that RNA typically:

• A. Is always double-stranded and forms a stable double helix in cells
• B. Contains ribose sugar and uses uracil (U) instead of thymine (T)
• C. Stores genetic information long-term in the nucleus as the primary hereditary material in most organisms
• D. Contains deoxyribose sugar and uses thymine (T) instead of uracil (U)

Answer: (B)

Verified step by step guidance

1. Step 1: Understand the structural differences between RNA and DNA. RNA contains a sugar called ribose, whereas DNA contains deoxyribose, which lacks one oxygen atom compared to ribose.
2. Step 2: Recognize the nitrogenous bases present in RNA and DNA. RNA uses uracil (U) instead of thymine (T), which is found in DNA.
3. Step 3: Note the typical strand structure. RNA is usually single-stranded, while DNA is typically double-stranded and forms a stable double helix.
4. Step 4: Consider the functional roles. DNA stores genetic information long-term in the nucleus, whereas RNA is often involved in protein synthesis and other cellular processes.
5. Step 5: Based on these points, identify that the key distinguishing features of RNA are the presence of ribose sugar and uracil, rather than thymine, and that it is usually single-stranded.