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:

the relative atomic mass of an element is the mass of one atom of that element, relative to 1/12th of the mass of a  1212c atom. to convert to an absolute mass in kg, it is necessary to multiply by  1.661×10−271.661×10−27.

the relative atomic mass is roughly equal to the number of neutrons, plus the number of protons, in the nucleus of the atom.

for elements with more than one stable isotope (different types of nucleus with different numbers of neutrons but the same number of protons), the quoted mass is usually the average mass, weighted by the relative abundance of the different isotopes.

yes it is weird but true