6. Which form of renewable energy converts sunlight into electricity? hydroelectric

solar power

geothermal

biomass
7. What renewable biomass fuel source has been used for thousands of years?

corn

straw

sugarcane

wood
8. Which renewable form of energy is found in the Earth's crust?

coal

petroleum

geothermal

natural gas
9. What effect does the Earth's surface have on solar radiation?

Half of the solar radiation is absorbed and converted to infrared (heat).

Nearly all solar radiation is reflected back into space by the ground.

The ground absorbs half the solar radiation and stores it as infrared radiation for centuries.
10. Which greenhouse gas has the greatest effect on climate?

nitrous oxide

hydrofluorocarbons

water vapor

carbon dioxide