They may also appear on other parts of the body. Warts have a rough texture and are caused by viruses, particularly one of several kinds of HPV (human papillomavirus). The virus causes keratin, which is a hard protein on the top layer of the skin, to grow too fast. Warts are not the same as moles.
The tropical rainforest is a hot, moist biome found near Earth's equator. The world's largest tropical rainforests are in South America, Africa, and Southeast Asia. Tropical rainforests receive from 60 to 160 inches of precipitation that is fairly evenly distributed throughout the year. The combination of constant warmth and abundant moisture makes the tropical rainforest a suitable environment for many plants and animals. Tropical rainforests contain the greatest biodiversity in the world. Over 15 million species of plants and animals live within this biome.
Each rainforest is unique, but there are certain features common to all tropical rainforests. Location: rainforests lie in the tropics [map]. Rainfall: rainforests receive at least 80 inches (200 cm) of rain per year. Canopy: rainforests have a canopy, which is the layer of branches and leaves formed by closely spaced rainforest trees [picture].