What are the other words or phrase for fossil fuels?

Câu hỏi :

Read the following passage and choose the correct answer to the questions below.

          Almost all our energy comes from oil, coal and natural gas. We call them fossil fuels. The earth’s fossil fuels are running out. What would happen if there were no oil, coal and gas on earth?

Scientists are trying to find and use other alternative sources of energy. We can use energy from the sun, the wind and the water.

Solar energy is unlimited. It supplies all the energy used to grow plants, to evaporate water for rain, and to maintain the temperature of the planet. All are necessary for human life. If we are able to collect solar energy, we will be sure to have this abundant source of power.

What are the other words or phrase for fossil fuels?