Which is one of Edwin Hubble’s findings that supports the big bang theory? The universe started at a central point.
Planetesimals formed in debris disks.
Visible matter only makes up about 5% of the universe.
The Milky Way is the only galaxy in the universe.

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.