Answer:
x, y, and z I think that is it
The answer is 24
you do 6+6+6+6
For this case we have that by definition it is fulfilled:

Where:
a: It is the base
b: It is the exponent
So, if we have the following expression:
-6 to the power of 4, is equivalent to: 
So we have to:
-6: It is the base
4: It is the exponent
Answer:
-6: It is the base
4: It is the exponent
Energy is the correct answer