Question: What is a negative aspect of fossil fuels?

Answer: fuels that were formed millions of years ago from the remains of living organisms
Does this answer the question?

Yes, the answer provided describes the negative aspect of fossil fuels as being formed from the remains of living organisms millions of years ago. This can be considered a negative aspect due to the impact on the environment, such as air pollution and greenhouse gas emissions, as well as the finite nature of fossil fuel resources.