Warm and cold fronts are formed by the movement of different air masses.
a. true
b. false

B.a pop up at ion changes in response to a change in the environment.

The answer to this question is  c. pharmaceutical accumulation  reclaimed water refers to the water that being used again after it already  used for agricultural purposes.this type of water often contains pharmaceutical accumulation because of the chemical fertilizer that is used for the plants is absorbed into the water.

Ithink it is space that makes up 70 percent