If 30% of the bases within a DNA molecule are adenine, what is the percentage of thymine?

20%

25%

30%

35%

30%.

Explanation:

DNA is the hereditary material of all the organism except some viruses. The four bases present within the DNA molecule is adenine, guanine, thymine and cytosine.

According to the Chargaff rule, the ratio of purines (adenine and guanine) to pyrimidines (thymine and cytosine) should be equal to one. This means the amount of guanine in DNA is equal to cytosine and the amount of adenine in DNA is equal to thymine. The adenine is 30% so the amount of thymine should also be 30%.

Thus, the correct answer is option (3).