Why do plants and trees exist?

Why do plants and trees exist?
Hasting through the mythical jungle,
Wondering why do plants and trees exist,
Plants are one of the biggest things we have hoped for,
Some plants came grow into a fruit,
Sometimes a vegetable,
Trees can clean carbon dioxide while it’s handling oxygen,
It balances Co2 and O2,
Trees are a very big part of environment,
Plants provides us daily needs,
We can’t always depend on the environment,
If we don’t cut down trees like we usually do,
Our environment possibly can stay with us,
Do you understand now?