Where does the carbon dioxide for photosynthesis come from in terrestrial plants?A. airB. soilC. lightD. plant's foodE. water

Answer and Explanation

In terrestrial plants, the primary source of carbon dioxide (CO₂) for photosynthesis is the atmosphere. During photosynthesis, plants use sunlight to convert carbon dioxide and water into glucose and oxygen. The carbon dioxide enters the plants through tiny openings on their leaves called stomata.

1. Air (Correct Answer): The atmospheric air contains carbon dioxide, which is essential for the photosynthetic process.

2. Soil: While soil contains organic matter and nutrients, it is not a direct source of carbon dioxide for photosynthesis.

3. Light: Light is necessary for photosynthesis but does not provide carbon dioxide.

4. Plant's Food: Plants produce their own food (glucose) during photosynthesis, so this is not a source of CO₂.

5. Water: Water is another reactant in photosynthesis but does not supply carbon dioxide.

Conclusion

The correct answer to the question is A. air. Without the carbon dioxide absorbed from the air, terrestrial plants would be unable to perform photosynthesis effectively.