内容介绍：()1 2 34 5 6 7 8 9 101 2 3 41 234= 5: 10 10= ,20 ,40 ,? 20 1/4=56: 10 1020 ,? 20 (1/2)2=520 ,DNA1 2 3 3. 4.DNA1 2 20C H O N P S K Ca Mg Zn Mo Cu B Fe MnC H ON PS CH ONC OH 3410.1g/ml NaOH0.05g/ml CuSO