Describe the changes that occur inside a helium balloon as it rises from sea level I'll know if you g. oo. gle it, so please do it in your own words at least

Which of the following is not a physical property of mattera. melting pointb. heat of combustionc. viscosityd. boiling point

Are formed where bumps from two surfaces come into contact ?

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.