A:5:3
B:3:5
C:2:5
D:3:2
下列物态变化,需要吸热的是( )
①目的基因 ②引物 ③四种脱氧核苷酸 ④DNA聚合酶等 ⑤mRNA ⑥核糖体
These are my____ (sheep/horse) and that is my ____ (pig/pigs).