Answer: 20%
Explanation:
Recall that the sum of all nitrogenous bases is equal to 100%.
Hence: A + C + G + T = 100%
Now, since adenine nucleotides is 30%, then thymine is 30% as well (A = T). Thus, the total of both is 60%.
From 100 remains 40% which is divided equally between guanine and cytosine, so each is 20%.
Thus, the percentage of the same DNA molecule that would be expected to be guanine nucleotides is 20%
