The following are complementary bases in DNA:Group of answer choicesadenine and thymine.adenine and cytosine.guanine and thymine.guanine and uracil.

Understanding Complementary Bases in DNA

To determine which bases in DNA are complementary, it's important to know the base pairing rules established by Watson and Crick. The nitrogenous bases in DNA pair as follows:

1. Adenine (A) pairs with Thymine (T).
2. Cytosine (C) pairs with Guanine (G).

Analyzing the Choices

1. Adenine and Thymine: This is a correct pair according to the base pairing rules.

2. Adenine and Cytosine: This is incorrect because adenine does not pair with cytosine.

3. Guanine and Thymine: This is also incorrect as guanine pairs with cytosine, not thymine.

4. Guanine and Uracil: This is not applicable to DNA; uracil is found in RNA, not DNA.

Final Answer

The correct complementary base pair in DNA from the given options is adenine and thymine.