Compare Potential Energy Practice Test

A box is moved between two shelves. Shelf A is at height $h=1\text{ m}$ and Shelf B is at height $h=4\text{ m}$ (measured from the floor). Which shelf gives the box greater gravitational potential energy, and why?

A rock is dropped from a cliff at $h=12\text{ m}$ above the ground (take ground as $h=0$). As the rock falls toward the ground, what happens to its gravitational potential energy?