What is a substrate? a molecule that changes state a place where the reaction occurs a place on the product where the enzyme fits a reactant that is catalyzed by an enzyme

The accurate answer is:
A reactant that is catalyzed by an enzyme

A molecule that changes state
A place where the reaction occurs
A place on the product where the enzyme fits
*These answers right here are incorrect*
The answer behind this is
none of those answers above don't provide an complete understanding and they don't describe themselves. 

A reactant that is catalyzed by a enzyme is the correct answer.

When the ball is rising up, it gains kinetic energy. when the ball reaches the very top, it will have all potential energy, until it falls back down and gains it kinetic energy. finally when you catch the ball or it falls back down, it would have gained its potential energy back.