2.  A. water  B. wind  C. heat  D. coal

4.  A. oil  B. petroleum gasoline  C. natural gas  D. water

6.  A. Renewable energy is better for the environment.  B. Renewable energy is not going to run out anytime soon.  C. Renewable energy is easier to use.  D. both A and B

8.  A. running  B. jumping  C. eating  D. throwing a ball

10.  A. light energy  B. solar energy  C. chemical energy  D. geothermal energy

12.  A. windmill energy  B. biomass energy  C. conduction  D. solar energy

14.  A. convection  B. conduction  C. radiation  D. hydroelectric

16.  A. heat  B. work  C. force  D. eat

18.  A. solar energy  B. potential energy  C. geothermal energy  D. biomass energy

20.  A. fire  B. water  C. wind  D. chemicals

22.  A. kinetic energy  B. conduction  C. potential energy  D. chemical energy

24.  A. radiation  B. conduction  C. convection  D. fossil fuels

26.  A. light energy  B. heat energy  C. geothermal energy  D. solar energy

28.  A. wind; airplane  B. sun; solar  C. water; hydroelectric  D. wind; windmill

30.  A. solar  B. light  C. heat  D. chemical

32.  A. energy  B. work  C. power  D. radiation

34.  A. potential energy  B. chemical energy  C. biomass energy  D. kinetic energy

36.  A. hydroelectric energy  B. mechanical energy  C. light energy  D. heat energy

38.  A. convection  B. conduction  C. radiation  D. kinetic

40.  A. wood  B. coal  C. oil  D. natural gas