How can plants change the environment?

First of all, plants change the environment by saturating it with oxygen. It was thanks to plants in ancient times that the composition of the Earth’s atmosphere changed so much that ancient amphibians that emerged from water bodies could live and breathe on it. The more plants there were on the planet, the more its atmosphere was saturated with oxygen. In modern cities, plants, such as trees of certain species (poplars), are planted to absorb carbon dioxide and other harmful substances (vehicle exhaust).