Question

which of these is a fossil fuel?
○ algae oil
○ biodiesel
○ natural gas
○ firewood
need help on this question?
read the ebook page on this topic (no penalty) get a hint (fewer points) show answer (no points)

Explanation:

Fossil fuels form from ancient organic matter over millions of years. Natural gas is a fossil fuel, while algae oil, biodiesel, and firewood are renewable biofuels/biomass.

Answer:

natural gas