In the absence of air resistance, a falling rock gains kinetic energy and loses potential energy, while the total energy of the rock remains constant. in the presence of air resistance, however, the rock eventually reaches terminal velocity. now the kinetic energy is constant, but the potential energy continues to decrease as the rock falls toward the ground. why is some energy missing?

Total energy of a system always remains constant

Explanation:

In this particular case a work against air resistance  have to be done, and this is equal of the decrease in potencial energy.

The principle of energy conservation sates that energy is not created  or lost

but is transformed

a

explanation:

no diagram was provided, but i'm guessing it's the one i've attached to my answer.

here, a mechanical force turns the rod.   this generates an electric current in the coil, which powers the bulb.

it would be c. predictability