Instructions: Given a scientific passage and an answer, generate a question for the given answer.
Input: Passage: Fossil fuels are mixtures of hydrocarbons that formed over millions of years from the remains of dead organisms. They include petroleum (commonly called oil), natural gas, and coal. Fossil fuels provide most of the energy used in the world today. They are burned in power plants to produce electrical energy, and they also fuel cars, heat homes, and supply energy for many other purposes. You can see examples of their use in Figure below . Answer: fossil fuels
Output:
What is the common name of mixtures of hydrocarbons that formed over millions of years from the remains of dead organisms?