Highpoints of a range of hills or mountains

A stream feeding into a larger river, lake etc..

An ecosystem where all water runoff drains into a single body of water. All the land that drains water into a creek, river, lake, bay, or ocean.

Natural environment, an area of grass, trees, or other vegetation set apart for recreational or aesthetic purposes in an otherwise urban environment. 

This process describes how water evaporates from the surface of the earth, rises into the atmosphere, cools and condenses into rain or snow in clouds, and falls again to the surface as precipitation.

An individual living thing, plant, animal, bacterium, fungus, or other single-celled life form. All living (biotic) things consist of one or more cells.

Non living component of an ecosystem

Living component or once living component of an ecosystem