2. Thymine in DNA is replaced by uracil in RNA. What is the structural difference between thymine and uracil? (A) Thymine has one methy! group in its structure whereas uracil does not. (B) Thymine has one primary amine group in its structure whereas uracil does not. (C) Uracil has one methy! group in its structure whereas thymine does not. (D) Uracil has one primary amine group in its structure whereas thymine does not. (E) Uracil has a two-ringed structure, whereas thymine has a single-ringed structure.