Fill in the blanks with appropriate words:

• _______________________  radiant energy (mostly visible light and infrared radiation) produced at the Sun’s outer surface and radiated out into space.
• Electricity is produced naturally—_______________________________—but not in a form that we can use
• _______________________ and ________________________ are large continuous sources of thermal energy.
• __________________________________a source of energy that has been widely used for many years.
• __________________________ is one of the most controversial of all energy sources.
• Earth’s temperature depends on how much energy is absorbed by the atmosphere, and on how much energy radiates into space. This is known as __________________________________.
• Gases such as water vapour, carbon dioxide, methane, and nitrous oxides that trap energy in Earth’s atmosphere are known as _________________________.
• ____________________ _______________sources include wind, waves, solar energy, geothermal energy, and biofuel.
• Heating caused by the passage of radiant energy through the windows of a building is known as _____________ _______________ ________________.
• ________________________ a liquid fuel, such as ethanol, produced from plant or animal material.