November
20
In the past of 200 years, humans have caused the process to speed up. As the human populations grow, people keep building houses and factories in fields and woods. As they spread over the land, they destroy animals' homes. If the animals can't find a place to live, they die out. Besides that, over hunting is another way that humans are causing some animals to become extinct. In some part of the worlds, the parts of rare animals are worth a lot of money. Humans are also polluting the air, water, and soil and the effect of the pollution on animal species can be complicated. Finally, when humans introduce new species into certain environments, the animals that already live there become threatened and face extinction.
