Answer:
d. Potential energy changes to kinetic energy.
Step-by-step explanation:
Gravity pulls water down a slope, causing it to gain kinetic energy as it moves. At the top of the slope, the water has the most potential energy, which is the energy an object possesses due to its position or state. As the water moves down the slope, it converts its potential energy into kinetic energy, which is the energy an object possesses due to its motion. The kinetic energy of the water increases as it moves faster down the slope, and its potential energy decreases as it moves lower. This conversion of potential energy to kinetic energy is due to the force of gravity acting on the water, which accelerates it down the slope. Therefore, the correct answer is that potential energy changes to kinetic energy as gravity pulls water down a slope.