Solar Power Requires Backup Systems for

Q16: The elemental gas hydrogen is abundant in

Q17: Advantages of wind power are<br>A)high net energy

Q18: Active solar heating requires a _ between

Q19: Plug-in hybrid vehicles may require the burning

Q20: The major user of solar hot water

Q22: Akron, Ohio, which averages 201 cloudy days

Q23: As a general rule, winter thermostat settings

Q24: Light bulbs are now rated in _

Q25: The Earth's core maintains a temperature of<br>A)200

Q26: Light-emitting diode (LED) bulbs last _ times