Protist are a. members of the plant kingdom. b. prokaryotes. c. reclassified as scientists learn more about their diversity. d. more like other protists than members of other kingdoms.

C would be the best choice. Protists are eukaryotes that basically aren't members of fungi, plantae, or animalia. There is ongoing debate about their taxonomy. 

When the ball is rising up, it gains kinetic energy. when the ball reaches the very top, it will have all potential energy, until it falls back down and gains it kinetic energy. finally when you catch the ball or it falls back down, it would have gained its potential energy back.