- A Guanine
- B Cytosine
- C Thymine
- D Uracil
Correct answer: C. Thymine
Explanation: Adenine pairs with Thymine in DNA (2 hydrogen bonds). Guanine pairs with Cytosine (3 hydrogen bonds). In RNA, Adenine pairs with Uracil.
Concept context
Carbohydrates, proteins, lipids, nucleic acids, and enzyme kinetics. Essential foundation for understanding metabolism.