When a cat drops from a tree to the ground, the conversion of _____ takes place. Then the cat runs up behind a mouse to obtain its food. After eating its prey, the _____ takes place inside the cat's body.
a) gravitational potential energy to kinetic energy; conversion of chemical energy to mechanical energy
b) mechanical energy to nuclear energy; conversion of chemical energy to nuclear energy
c) nuclear energy to chemical energy; conversion of kinetic energy to chemical energy
d) chemical energy to nuclear energy; conversion of gravitational potential energy to mechanical energy