18. Which of the choices below best describes Uranium and Coal as an energy resource?
a. Petroleum
b. Fossil fuels
c. Renewable
d. Non-renewable

19. What is the main source of energy of the planet Earth?
a. Minerals
b. Water
c. Soil
d. Sun

20. What term best describe the distinct layer of the soil?
a. Soil profile
b. Soil layer
c. Regolith
d. None of the answer is correct

21. What is the main goal of sustainable development?
a. Responsible regeneration
c. Pollution control
b. Economic growth
d. all of the above

22. Which of the terms below, results to global warming?
a. Climate change
c. enhanced greenhouse effect
b. Weather changes
d. all a, b and c answers are correct.

23. What energy resource generates electricity from the falling or flowing water?
a. Solar energy
c. geothermal energy
b. Hydroelectric energy
d. dendrothermal energy

24. Why we need to conserve energy and make Earth a sustainable planet?
a. It is the only living planet in the solar system. b. It is the planet of extra-terrestrial.
c. It is the only planet with water.
d. It is known as mother earth​