Read the following passage and mark the letter A, B, C or D on your answer sheet to indicate the correct option that best fits each numbered blank from 19 to 24.
Most of our energy comes from fossil fuels (19) _____ coal, oil, and natural gas. Although the supplies of these energy sources are plentiful, they are limited. The (20) _____ of coal and oil is also having very harmful impacts (21) _____ the environment. However, fossil fuels are not the only source of energy and burning fuel is not the only way to produce heat and motion. Renewable energy offers us a better way.
Some energy sources are renewable because they are naturally available (22) _____ last forever. Some sources have enormous supply so human can never use them up. Moreover, renewable energy sources have much smaller impacts on the environment than fossil and nuclear fuels. (23) _____ include solar energy, which comes from the sun and can be converted into electricity and heat. Wind, geothermal energy from inside the earth, biomass from plants, and hydropower from 1 water are (24) _____ renewable sources of energy.