I would go with choice C) Pollution or the 3rd option.
Answer:
Carbon dioxide is released when fossil fuel is burned in the atmosphere. The fossil fuels are made of hydrocarbon and once it is burned in air carbon dioxide is released into the environment.
Carbon dioxide is one of the most important gases present in the atmosphere which constitutes of about 95 per cent of the the whole atmospheric gases.
Carbon dioxide is one of the main green house gases that helps in the absorbing heat from the atmosphere. It makes the temperature suitable for the organism to live on earth.
Carbon dioxide is a waste product of cellular respiration which is released inside the body an is expelled into the outer atmosphere.
