The correct answer is e) adenine and thymine.
In DNA, the bases pair up in a specific manner due to hydrogen bonding, which is known as base pairing. Adenine (A) is always complementary to thymine (T), meaning that in a double helix structure, A on one strand will pair with T on the opposite strand. This pairing helps to stabilize the DNA structure, ensuring that the genetic information can be reliably copied and transmitted during cell division.
To clarify further, the other options can be analyzed as follows:
- a) thymine and guanine: Thymine pairs with adenine, while guanine pairs with cytosine, making this option incorrect.
- b) guanine and uracil: This pairing does not occur in DNA; instead, uracil is found in RNA where it pairs with adenine.
- c) cytosine and adenine: Cytosine pairs with guanine, not adenine, thus this option is also incorrect.
- d) adenine and guanine: Both of these bases do not pair with each other; adenine pairs with thymine, and guanine pairs with cytosine.
Therefore, the only correct complementary base pairing in DNA from the options provided is adenine and thymine.