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.
True tropical rainforest -- equatorial evergreen rainforest -- typically receives at least 2,000 millimeters (80 in.) of annual rainfall, but the wettest may get 10,000 millimeters (304 in.) or more. The rain falls year-round, because there are no warm and cool seasonal changes to affect rainfall amounts.