Question

in animal cells, much of the carbon dioxide produced is
a. used for energy.
b. converted to sugar.
c. excreted as waste.
d. stored in vacuoles.
e. recycled.

Explanation:

• Option A: Energy in cells comes from glucose breakdown, not CO₂ use. Eliminate A.
• Option B: Converting CO₂ to sugar is photosynthesis (plant cells), not animal cells. Eliminate B.
• Option C: Animal cells produce CO₂ via respiration; it's excreted (e.g., via lungs, skin). This fits.
• Option D: Vacuoles store substances, but animal cells have small vacuoles, and CO₂ isn't stored there. Eliminate D.
• Option E: Animal cells don't recycle CO₂ for major use; they excrete it. Eliminate E.

Answer:

C. excreted as waste.