Question

how would the burning of fossil fuels upset the balance of the carbon dioxide cycle?
a it decreases the carbon dioxide in the atmosphere
b it adds oxygen to the atmosphere
c it decreases oxygen to the atmosphere
d it increases carbon dioxide in the atmosphere.

Explanation:

When fossil fuels (like coal, oil, and gas) are burned, the chemical reaction \(C + O_2
ightarrow CO_2\) (for carbon - based fossil fuels) occurs. This releases carbon dioxide (\(CO_2\)) into the atmosphere. In the carbon dioxide cycle, plants usually take in \(CO_2\) for photosynthesis (\(6CO_2+6H_2O
ightarrow C_6H_{12}O_6 + 6O_2\)), but the rate of fossil - fuel burning is so high that the amount of \(CO_2\) released exceeds the capacity of natural sinks (like plants and oceans) to absorb it.

• Option A: Burning fossil fuels does not decrease \(CO_2\) in the atmosphere. Instead, it releases \(CO_2\).
• Option B: Burning fossil fuels consumes oxygen (\(O_2\)) (from the reaction \(C + O_2

ightarrow CO_2\)) rather than adding it.

• Option C: While burning fossil fuels consumes \(O_2\), the main impact on the carbon - dioxide cycle is the addition of \(CO_2\), not the change in \(O_2\) levels in terms of the carbon - dioxide cycle.
• Option D: As explained above, burning fossil fuels releases \(CO_2\) into the atmosphere, increasing its concentration.

Answer:

D. It increases carbon dioxide in the atmosphere.