Answered

In human DNA, adenine (A) makes up approximately 30.9% of the bases, and

guanine (G) makes up approximately 19.9% of the bases; therefore the percentage thymine (T) and cytosine (C) are

A19.8% T and 19.8% C.
B19.8% T and 29.4% C.
C29.4% T and 19.8% C.
D29.8% T and 29.8% C.
E19.9% T and 30.9% C.

Can you please explain with some details?

Verified Answer :

In human DNA, there are nitrogenous base pairings- A, T C and G. A pairs with T and C pairs with G. Because they're a pair, the ratio of A:T and C:G should be as close to 1:1 as possible. Since A makes up approx 30.9%, T should be either C or D. As G makes up approx 19.9%, we can rule out option D, therefore the answer is C! Hope this helps (: