Since its beginning, life has relied upon the sun to sustain a good climate on Earth. Now, the use of solar energy is starting to be viewed as a great, non-polluting means of energy. Solar energy is already being used as a source of heat. The principle that a black surface exposed to the sun will absorb solar energy is the basis of several million domestic hot water heaters used in a dozen countries, including Japan, Australia and Israel. A more advanced system could be applied to home heating and cooling. If solar energy someday replaces oil and coal, we will enjoy more power, cleaner air, and better health.

Q. List the three advantages of using solar energy.