A(n) is defined as the interrelationship between living beings and environment.

a. ecosystem
b. life support system
c. climate system
d. atmospheric system

i believe it is d but i'm not sure.

The correct answer is A. An ecosystem is the relation between living and nonliving organisms living together to make it work. An atmospheric system, like the word says, is one of the Earths many layers composed of mainly oxygen and nitrogen. Its location is 10 miles from Earths surface and is 300 miles thick.

I'm pretty sure it's c. extremely gradual but not 100% sure though.

Answerhave flowing water either episodically or during only a portion of the year;