Rainforest cover only 2 % of the total surface area of the Earth but in spite of that about 50 % of plants and animals that live on the Earth live there.
By definition rainforests are forests that recieve high amounts of rainfall so you can actually find rainforests in Alaska for example (other examples: Canada, Asia, Africa, Latin and South-America)
About 1/4 of natural medicines are found in rainforests. 70 % or more of the plants that are used to treat cancer are found only in tropical rainforest on the planet.
Trees in tropical rainforests are so dense that it takes approximately 10 min for the rainfall to reach the ground from canopy.
If a plant uses up all of the carbon dioxide this would just keep makeing oxygen or its known as photosynthesis. I'm NOT a 100% sure If this is is the correct answer or not.
