Me i need your the tobic is human impact
here is my qustion

can be accidental or intentional, and it can cause erosion.

fire

water pollution

septic leaks

irrigation

Its decreasing because of illnesses

Answerjoe ran 130 yards;

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.

The answer is that they depend on rainfall for their crops to grow. hope this .