Question

Choose the correct statements:
(a) DNA does not contain uracil
(b) RNA does not contain thymine
(c) RNA and DNA both have uracil
(d) RNA has both uracil and thymine

• A. a, b
• B. c, d
• C. a, c, d
• D. b, c

Hint:

DNA uses thymine while RNA uses uracil at corresponding positions.

Answer 1

The Correct Option is A

Step 1: Understand nucleic acid bases.
DNA contains bases adenine, guanine, cytosine, and thymine. RNA contains adenine, guanine, cytosine, and uracil instead of thymine.

Step 2: Evaluate statement (a).
DNA does not contain uracil; it contains thymine instead. Hence (a) is correct.

Step 3: Evaluate statement (b).
RNA does not contain thymine; it uses uracil in place of thymine. Hence (b) is correct.

Step 4: Evaluate statement (c).
Both DNA and RNA do NOT contain uracil simultaneously; DNA lacks uracil. Hence (c) is incorrect.

Step 5: Evaluate statement (d).
RNA does not contain both uracil and thymine; it contains only uracil. Hence (d) is incorrect.

Step 6: Final conclusion.
Only statements (a) and (b) are correct.
Final Answer: \[ \boxed{a,\ b} \]