The is made up of all of earth's land and the ocean floors.
a. atmosphere
b. lithosphere
c. hydrosphere
d. biosphere

The diagram shows the positions of the sun, moon and earth during spring tides, when the high tides are at their highest and low tides at their lowest. what is it about these positions that causes these high and low tides?

Which part of a mountain receives the majority of moisture due to the rain shadow effect? a. the leeward side b. the windward side c. the bottom of the mountain d. all parts of the mountain receive equal amounts of moisture.

What is the amount of organic matter in all living organisms in a habitat called?