Answer: Fossil fuel is burned in the presence of oxygen to release energy and carbon dioxide and heat.
Explanation:
The combustion of fossil fuel release enormous amount of energy in the form of heat which is used to perform various tasks. This process also releases some amount of carbon dioxide.
Fossil fuels are formed by the compression of biomass deep inside the earth that takes thousands years to get converted into fossil fuel.
I think the answer is d because the bodys first line of defense is both physical and chemical barriers ect. skin, tears, mucus, cilia, stomach acid and urine flow
