What occurs during electrolysis? low-energy reactants become high-energy products. high-energy reactants become low-energy products. unreactive elements become reactive elements. reactive elements become unreactive elements.

Low-energy reactants become high-energy products.  

Explanation:

In electrolysis, you are forcing a reaction to occur that otherwise wouldn't happen.

You are pumping energy into the system and converting low-energy reactants into high-energy products.

B is wrong. Nature tends  to run downhill energetically, so high-energy reactants tend to form low-energy products spontaneously.

C and D are wrong. If an element is unreactive, it stays unreactive, and vice versa. You can't change the nature of an element.

c- cold periods in earth's history during which glaciers covered much of the surface.

explanation:

answer; natural resources;