Answer:
A. pulls back on the Earth, which is the main cause of the rise and fall of the ocean tides on Earth.
No. Mechanical energy is not conserved. There's quite a bit of friction on the slide. So some of the potential energy is lost to heat on the way down, and the child arrives at the bottom with hot pants and less kinetic energy than you might expect.
I believe the answer is "When a neutral atom looses an electron to another neutral atom, two charged atoms are created."
