Answer:
(a) 21% of the human genome is comprised of G.
(b) 29% of the human genome is comprised of T.
(c) 29% of the human genome is comprised of A.
Explanation:
According to Chargaff's rule, a DNA molecule has the same amount of pyrimidines (T and C) as purines (A and G), and G pairs with C and A pairs with T.
If 21% of the genome contains C, then 21% also contains G.
Therefore 21% + 21% = 42% of the genome is comprised of G+C.
The other 58% is comprised of A+T, and because they pair with each other, 29% will correspond to A and 29% will correspond to T,