Humans and animals use the oxygen (O2) in the air for their energy process and produce CO2 as waste. ... A plant derives energy from the CO2 and produces O2 as waste. If there were no plants on the planet we wouldn't be able to breathe.
Plants form the base of the food chain. Herbivores eat plants exclusively. In turn, herbivores are eaten by carnivores. Without plants, herbivores wouldn’t be able to survive and without the herbivores, carnivores wouldn’t be able to survive.