Why do tropical rainforests have a variety of plants and animals?

Climate: because rainforests are located in tropical regions, they receive a lot of sunlight. This energy is stored in plant vegetation, which is eaten by animals. The abundance of energy supports an abundance of plant and animal species.

when atoms of different types of elements join together, they make molecules called compounds. water consists of compound molecules made up of 2 hydrogen atoms and 1 oxygen atom. this is why it's called h2o. water will always have 2 times the number of hydrogen atoms as oxygen atoms.