If 30% of the bases in a particular DNA molecule are guanine (G), calculate the percentage of thymine (T) bases. Explain your reasoning.

In a DNA molecule, the amount of guanine (G) is always equal to the amount of cytosine (C), and the amount of adenine (A) is always equal to the amount of thymine (T). This is due to the specific base pairing in DNA: A pairs with T, and G pairs with C.

Given that 30% of the bases are guanine, this means that 30% of the bases are also cytosine. Therefore, G and C together make up 60% of the bases.

Since A and T must make up the remaining 40% and A equals T, then thymine (T) must make up half of that 40%, which is 20%.

So, the percentage of thymine (T) bases in the DNA molecule is 20%.