Abby and I did the nitrogen cycle. First the nitrogen comes out of a factory. Then it goes up into the air and clouds. Then the nitrogen comes down from the clouds as rain and lightning. Next the nitrogen is in the plants and waters. Then the animals eat and drink the nitrogen in the water or plants. Then the nitrogen is in the animals and they decompose the nitrogen as poop. Then the poop goes into the air and clouds and the cycle continues over and over again.