Answer: Atmosphere is made up of air, hydrosphere contains all living things, Evaporation is necessary to water circle while precipitation is not always necessary and the amount of water on earth never changes but the state could.
Explanation:
The biophysical elements of the earth are divided into four spheres which include biosphere, lithosphere, hydrosphere and atmosphere.
The biosphere is the biophysical element that contains living things/organisms.
The lithosphere is the sphere that contains the land or soil.
Hydrosphere is the biophysical element housing the waters while atmosphere contains the air including all its components like oxygen, carbon dioxide, neon amongst others.
As regards the difference between evaporation and precipitation, Evaporation has to do with the change in state from liquid to gas especially as it concerns water and it’s very important to the water circle while precipitation refers to the process whereby it falls off from the sky eg rainfall but it’s not really necessary for the water circle.
As for the last question (8), the amount of water available is always constant but can change states ie from solid (ice) to liquid to gas
