Plants are very important on Earth because the whole ecosystem of life needs plants.
Herbivores eat all kinds of plants. Even though leaves don't have a lot nutrients animals still eat them. Actually it's really dangerous to do that because the plants has many defense mechanisms.
The plants in the wild are pretty dangerous. Some have poison as a defense mechanism or spikes. Some animals know a secret way to kill the poison though.
The Reason Why Earth Needs Water and Plants
Earth needs water to keep the animals the plants alive so they can redo the circle of life. We need plants to help the circle of life going. We need these to things for nutrients.
Hope you enjoyed.