Question

The main waste products of plants are

• A. CO${}_2$ and NO${}_2$.
• B. CO${}_2$ and water vapour.
• C. CO${}_2$, O${}_2$ and water vapour.
• D. None of the above.

Answer 1

The correct option is C CO${}_2$, O${}_2$ and water vapour.

Plants eliminate some waste through diffusion. During the day, excess oxygen gas produced by photosynthesis is released through the stomata. Carbon dioxide produced by respiration is normally used up during photosynthesis. At night, however, as photosynthesis slows, carbon dioxide is not used up as fast as it is produced, and it is released as a waste product. Plants also release waste water by transpiration and guttation.

Therefore, the correct answer is option C.