12. Which is a disadvantage of using solar or wind energy to produce electricity?
A. They are controlled energy resources
B. These energy sources are nonrenewable
C. They are an expensive way to produce energy
D. Their ability to produce energy is inconsistent and variable

C. or D.

Explanation:

C. Having Solar Energy panels are very expensive

D. Solar Energy can only be produced whenever the sun is out and Wind energy can only be produced when it's a windy day/if there's wind

the correct answer is option d

explanation:

i was wrong its d because they dont use cm when calculating square roots