HELP!! In the EXPLORE section of your lesson 4.08 on Potential energy there were several animations to watch that provided a graphic illustrating how the PE and KE in a system changed as skateboarder rides a pipeline or a pendulum moves, why did the bar for the total energy remain constant?

Question 1 options:

A. Because these models do not take into account the impact of friction and air resistance and are helping to solidify the concept of energy conservation and that the total mechanical energy remains constant in that model.

B. This is because no energy is being created or destroyed in this system.

C. Energy is converted from kinetic to potential and potential to kinetic, but the total amount of energy is conserved.

D. all answers given are correct