What's the best thing we as human beings can do to help the earth?

My answer would be : plant trees, honestly. There are so many trees that are being chopped down due to deforestation because our population is expanding so rapidly, and trees help out environment a lot due to the fact that they release oxygen into the atmosphere and create more ecosystems for animals. If more trees are planted, more animals are given homes, and more oxygen is in the air, then the earth can perhaps start to rebuild itself faster than we’re destroying it.