生物分类是研究生物的一种基本方法,最基本的分类单位是[ ]
A.门
B.纲
C.科
D.种
答案:D
Mr. Johnson, together with his wife and two daughters, ____ to arrive on the evening flight.
A.are going
B.are
C.will be
D.is going
蛹的生物学意义是什么?其基本类型有哪些?