The analysis of a DNA molecule reveals that 30% of its nucleotides are adenine. What percentage of the same DNA molecule would be expected to be guanine nucleotides?

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%

condenser is used to focus in the light microscope.