How does a hydrosphere behave as a system

It is a closed system, the earth operates on a water budget in which deficits in one part are balance by gains in another part

In forms of a liquid surface water, ice and under ground flow.

Explanation:

The hydrosphere is a sphere f the water cycle that operates in a systematic manner form the evaporation in the surface water from lakes and river and seas to the condensation and then precipitation over the surface again in snow, hail or rain and which is absorbed by plants and trees is given out by the leaf pores and the moisture on soil is infiltrated by pores and forms underground aquifers and this comes out to join the streams and again joins the ocean system.

Cause of he different elevations  hope this ?