this means humans could lose their food source from animals dying out and that would make every food source for animals go down.
factories pollute the air and the enviroment
this could kill animal such as birds and other animals that live near the factory
people pollute the water and that kills fish and now people cant swim in the water
Also it could kill fish and ruin the food chain killing more animals
when people use factories it pollutes the water because the extra oils get flushed out of pipes that lead to the ocean. this could lead to fish dying and peoples drinking water contaminated or even poisened.
when people cut down trees it is called deforistation. also this could cause the lose of animals habitats
when people use cars or busses it lets of carbion dioxide which is a gas that if you breath in you could die
you may not think about it but when you build blaygrounds your destroying animals habitats