Which option shows the correct DNA base pairing?

Which option shows the correct DNA base pairing?

• A. Cytosine with Guanine and Adenine with Thymine
• B. Cytosine with Adenine and Guanine with Thymine
• C. Adenine with Uracil and Guanine with Cytosine
• D. Adenine with Cytosine and Guanine with Thymine

Answer: (A)

DNA base pairing follows a precise rule: adenine pairs with thymine and cytosine pairs with guanine. This pairing is stabilized by hydrogen bonds (two between A and T, three between C and G), which helps keep the double helix intact and allows accurate replication and transcription. Therefore, cytosine pairing with guanine and adenine pairing with thymine matches these DNA rules. The other options mix bases that don’t pair together in DNA (such as cytosine with adenine or guanine with thymine), or bring in uracil, which is used in RNA instead of thymine.

DNA base pairing follows a precise rule: adenine pairs with thymine and cytosine pairs with guanine. This pairing is stabilized by hydrogen bonds (two between A and T, three between C and G), which helps keep the double helix intact and allows accurate replication and transcription. Therefore, cytosine pairing with guanine and adenine pairing with thymine matches these DNA rules. The other options mix bases that don’t pair together in DNA (such as cytosine with adenine or guanine with thymine), or bring in uracil, which is used in RNA instead of thymine.