All of the following are false except

a. foreshocks cannot happen before an earthquake
b. aftershocks cannot happen after an earthquake
c. foreshocks and aftershocks can happen at the same time
d. foreshocks and aftershocks cannot happen at the same time

The answer is D foreshocks and aftershocks cannot happen at the same time.

When a lake, river or other aquatic  system  becomes  eutrophic, it can have serious negative effects on other organisms like fish, birds and even people.if an algal bloom is so bad that it causes wide-spread death  in  the  water, the organisms that die will all sink to the bottom and start to decompose.