Question

lesson 1
carbon cycle and the ocean
(1 point)
○ because they cause a lot of pollution
○ because they cause a decrease in the amount of nitrogen in the atmosphere when burned
○ because they are rich in carbon, which is a greenhouse gas
○ because they cause holes to form in the ozone

Explanation:

1. Analyze Option 1: While fossil fuel combustion does cause pollution, the question likely relates to the carbon cycle (from the diagram). This option is too general.
2. Analyze Option 2: Fossil fuel burning does not primarily affect atmospheric nitrogen levels; it's about carbon, so this is incorrect.
3. Analyze Option 3: Fossil fuels (like coal, oil) are rich in carbon. When burned, they release $\ce{CO_2}$, a greenhouse gas, which ties to the carbon cycle (as seen in the diagram with combustion of fossil fuels releasing carbon - related gases). This matches the context of the carbon cycle and climate change.
4. Analyze Option 4: Ozone holes are caused by CFCs (chlorofluorocarbons), not fossil fuel combustion, so this is incorrect.

Answer:

The correct option is: Because they are rich in carbon, which is a greenhouse gas (the third option among the given choices, with the full text "Because they are rich in carbon, which is a greenhouse gas").