As we all know, animals and plants are interrelated!! They are very important to one another. so, if one of them became extinct, most probably, the other one will also get extinct and if you think more deeply,
1.people's consumption of plants and animals is much faster than their production
2.the animals cannot produce as much as they could because their habitats are being abused. For ex: the forest, and if their habitats are being abused, it will become hard for them to live.
3. Destruction of habitat also aids in extinction