What statement about the two DNA strands is true according to the material?

What statement about the two DNA strands is true according to the material?

• A. They are complementary
• B. They are identical
• C. They are unrelated
• D. One strand is RNA

Answer: (A)

The two DNA strands are complementary. In the double helix, bases on one strand pair with specific partners on the other: A with T and G with C. This base-pairing means the sequence on one strand determines the sequence on the opposite strand, so the strands are not identical even though they carry the same genetic information. They are antiparallel and both are DNA (deoxyribose and thymine), not RNA, so a strand being RNA isn’t correct. They aren’t unrelated because base pairing links the two strands into a cohesive double helix.

The two DNA strands are complementary. In the double helix, bases on one strand pair with specific partners on the other: A with T and G with C. This base-pairing means the sequence on one strand determines the sequence on the opposite strand, so the strands are not identical even though they carry the same genetic information. They are antiparallel and both are DNA (deoxyribose and thymine), not RNA, so a strand being RNA isn’t correct. They aren’t unrelated because base pairing links the two strands into a cohesive double helix.