What is the theory of plate tectonics, and what are two ways this theory has been beneficial society?

So sense there isn't an exact answer I'll just say what they are and how it benefited society, try to interpret it.

So the answer to the theory is, the plates that surround earth's first layer such as the land we're on or ocean, in this case continental crust (Land Crust) and oceanic crust (Crust on the ocean floor).

Explanation:

oceans

indian ocean

pacific ocean

atlantic ocean

arctic ocean

southern ocean