Question

read the following paragraph from the section carbs, proteins and fats.\
the cycle allows us to use the energy found in carbohydrates, proteins and fats. although the
citric acid cycle does not use oxygen directly, it only works when oxygen is around. this cycle
takes place in the mitochondria of the cell.
which idea is best supported by this paragraph?
(a) the presence of oxygen can sometimes impede the citric acid cycle of cellular respiration.
(b) carbohydrates, proteins and fats do not contain oxygen molecules needed for the citric acid cycle.
(c) the citric acid cycle will not occur unless oxygen is present within the mitochondria of the cell.
(d) oxygen is the main ingredient that the citric acid cycle converts and uses to make its final product.

Explanation:

• Analyze Option A: The paragraph says the cycle works when oxygen is around, so oxygen doesn't impede it. Eliminate A.
• Analyze Option B: The paragraph is about the cycle's dependence on oxygen presence, not about oxygen in carbs, proteins, fats. Eliminate B.
• Analyze Option C: The paragraph states "it only works when oxygen is around" and the cycle is in mitochondria. So the cycle needs oxygen present in mitochondria to occur. This matches.
• Analyze Option D: The paragraph says the cycle does not use oxygen directly, so oxygen isn't the main ingredient used. Eliminate D.

Answer:

C. The citric acid cycle will not occur unless oxygen is present within the mitochondria of the cell.