Plants release oxygen through the process of photosynthesis which helps the animals for respiration. They also maintain the balance of oxygen and carbon dioxide in the atmosphere. That is why the forests are called green lungs.
The process of fermentation will begin.
The main cause of extinction on Earth today is, Humans, we are the biggest
threat to our environments'.
Hope that helps!!!! ( We Humans, are our biggest enemy, and threat to ourselves, and he environment.).