It was rather strange how the habits of his youth clung to him still. He was 72.

A．stuck to

B．turned

C．led to

D．gave way to

根据基因与细胞分化的关系，将基因分为下列哪两大类（）

A.隔裂基因

B.奢侈基因

C.重叠基因

D.管家基因