Is the human species a keystone species? explain. if humans were to become extinct, what are three species that might also become extinct and what are three species whose populations would probably grow?

Yes, humans are a keystone species by virtue of their technology as well as the manner in which they influence their natural habitat. If humans were to become extinct, pets, livestocks, and crop plants would also follow. On the other hand, the species that would likely grow in number would be mountain gorillas, whales and weeds.  

It should be cryosphere and hydrosphere