So, from the looks of it, we need to define what PE is
PE = potential energy
Potential energy is the energy that is stored in an object due to its position relative to some zero position
In this case, the zero position is the ground.
Potential energy in a nutshell:
The more still you are (and higher from the ground) the more potential energy you will have. That is why it is called POTENTIAL. It has the potential to turn into something else, in this case, when the elephant starts to move, that potential energy will turn into kinetic energy and friction energy.
The equation also helps us better visualize the problem:
PEg = Gravitational Potential Energy
PEg = mgh
So, if you were to increase the height (h) in the equation, then the PE would increase as well, right?
That means if we decrease the height, the PE will decrease. I hope I haven't lost you yet.
This means that 10 m is the highest point, therefore the elephant has the most potential energy at 10 m, so when it starts to fall it will LOSE PE and that PE will be turned into other energies like kinetic energy.
Answer:
As the elephant falls from 10 m it will lose PE because the PE is at its highest at 10 m, and while it is falling the PE will turn into other energies such as kinetic energy.
Hope this was helpful! There are plenty of great videos about this, I recommend you check them out!