The photoperiodic response of algae actually depends on the duration of darkness, but not on the response of light.

A．is not on light

B．but is not on the light

C．and not on light

D．the light is not on

污染物在水中扩散，被水流冲走，此形式称为

A．污染物的迁移
B．污染物的转化
C．生物富集
D．水体富营养化
E．有机物腐殖质化