People, animals, and all matter on Earth are A. drawn toward the center of Earth by the planet's gravity

B. drawn toward other matter on Earth like the trees and the buildings, since all matter has gravity

C. not affected by Earth's gravity because people are so small in
comparison to the planet

D. held to Earth's surface by their own gravity

Hydroelectricity provides about 7 percent of the electricity generated in the united states. (a) explain how a hydroelectric power plant converts energy stored in water into electricity. (b) identify two factors that determine the amount of electricity that can be generated by an individual hydroelectricity power plant. (c) describe the two main types of land-based hydroelectric power plants. (d) describe two economic advantages and two environmental disadvantages of hydroelectricity.