The common house fly has nucleotides that are 28% cytosine. what percentage of thymine would be present.

Answer;

Thymine= 22%

Explanation;For a double stranded DNA, A = T and G = C, That is the base Adenine pairs with the base Thymine, while the base Guanine pairs with the base Cytosine.All the four bases in a DNA strand together must equal 100 percent of the sample.Therefore; if you know the DNA sample is 20 percent thymine, you automatically know it is 20 percent adenine, as well, since they pair together.Additionally, Since all four bases together must equal 100 percent of the sample. Then if, cytosine is 28%, then Guanine is 28%;

Thus, since G + C + T + A = 100 , and G = C and A = T

T + A = 100 -(C+G)

        = 100 - 56

        = 44 %

Therefore; Thymine = 44/2 = 22%

The correct answer is b