The rainforest is a very unique place that has a lot of prominent things from other biomes.  People call the rainforest the worlds largest pharmacy because a quarter of the world's medicine is found there. There are four layers in the tropical rain forest and it also   contains about 42,000 species of insects, 807 trees and 1500 kinds of plants. Scientists estimate that more than half of all the world's plant and animal species live in tropical rain forests. The tropical rainforest has been around for millions of years and is still healthy today.