Which of the following correctly describes the importance of the nitrogen cycle?

to recycle carbon dioxide in the atmosphere

to replenish carbon dioxide in the ground

to decompose dead animals

to provide plants with needed ammonia

Consider the following planned experiment. factor experimental group control group light exposure tots of sun tots of sun amount of water weekly weekly type of soil nutrient rich nutrient rich size of pot large which variable is being tested in this experiment? small a. size of pot b. type of soil c. light exposure d. amount of water