Câu hỏi 25

Ta có A=T; G=X

Mà: \(\left\{ \begin{array}{l}\frac{{A + T}}{{G + X}} = \frac{2}{3}\\A + G = 50\% \end{array} \right. \leftrightarrow \left\{ \begin{array}{l}\frac{A}{G} = \frac{2}{3}\\A + G = 50\% \end{array} \right. \to \left\{ \begin{array}{l}A = T = 20\% \\G = X = 30\% \end{array} \right.\)

Chọn C