It is ______ to spend money in preventing illnesses by promoting healthy living rather than spending it trying to make people ______ after they are ill.

A．good; good

B．well; better

C．better; better

D．better; good

下列有关基因控制生物性状的实例分析，属于直接通过控制结构蛋白合成来控制性状的是（）

A.白化病

B.苯丙酮尿症

C.囊性纤维病

D.豌豆粒型