Bones and skull is the answer
Answer:
Just before the cat drops, it was stationery. Therefore it has energy of position called potential energy.As it drops, the Gravitational potential energy is converted to Kinetic Energy,The conversion mid- air is P.E to K.E to P.E to K.E to P.E to K.E, until it touches the ground. As it touches the ground all the energy is converted to P.E energy of position.
As it runs after mouse the P.E is converted back to Kinetic , energy of motion. As it feeds on the mouse , the chemical energy obtained as protein from mouse meat.This is later converted back to Mechanical energy as (kinetic and Potential energy) in the cat.
Explanation:
A heart beat, breathing, and moving ;)
