They make a difference in temperature, rainfall, moderation of climatic conditions, level of air pollution, and the level of oxygen that we breathe.
(They; make; a difference in temperature, rainfall, moderation of climatic conditions, level of air pollution, and the level of oxygen) (the level of oxygen; breathe; we)
They the level of oxygen
make breathe
a difference in temperature, rainfall, moderation of climatic conditions, level of air pollution, and the level of oxygen
we