The Tropical Rainforest Biome is a place of year-round warmth and heavy rainfall. Anually, 125-660 centimeters (50-260 inches) of rain falls in rainforest biomes. Temperatures range from 20-34 degrees Celsius (68-93 degrees Farenheit) and humidity levels are 77-88%. The Tropical Rainforest has four major layers: the Emergent layer, where the largest treetops tower over the rainforest, the Upper Canopy, where most treetops are and most of the light is blocked, the Understory, where Upper Canopy tree trunks and high humidity are, and the Forest Floor, where new plants and animals live. Not only is the rainforest vital for those who live in it, but to those who don't as well. A quarter of our medicine is from the Tropical Rainforest Biomes. Curare is used as an anesthetic; Quinine treats malaria; Rosy Periwinkle gives patients with lymphocytic leukemia a 99% chance of survival. In fact, over 1,400 Rainforest plants are thought to be potential cures for cancer. The Rainforests, found in Central and South America, Central Africa, and Indo-Malaysia, provide 40% of the worlds oxygen despite facing dangers. Due to deforestation and other harmful practices, this biome now only takes up 6% of the world. See Slash and Burn section to read more on the disappearence of the Rainforests.