In the DNA of salmon there is 28% Adenine, and 28% Thymine. So the rest 44% of that will be Guanine and Cytosine. (Guanine pairs only with Cytosine) Therefore, Guanine and Cytosine will have same percentage, which will be 22% each in the DNA of salmon. And then Guanine and Cytosine together is 44%, like I already mentioned. So Guanine alone has 22%.
