Why do plant use nitrogen in their own form?

In iceland, the mid atlantic ridge runs through the center of the contry. what can you conclude about the apperence of iceland many thousands of years from now?

Omg substrates with the same size and shape as the active site will bind to the enzyme. why is the key labeled the “bad” substrate?

What is point source pollution of an aquatic ecosystem? a) pollution of freshwater sources b) pollution from many sources that combine into one c) pollution that occurs over a wide area; water that runs off from fields, parking lots, and other land surfaces d) pollution that can easily be identified with a single discharge source, such as an open pipe which drains into a body of water