(a) Design an experiment to demonstrate that carbon dioxide is essential for photosynthesis. Write the observation and conclusion of the experiment. OR In the experimental set- up shown above in diagram (I) atmospheric air is being passed into lime water with a syringe while in diagram (II) air is being exhaled into lime water. The time taken for the lime water to turn milky in both the test tubes is different. Give reason. (ii) Draw the diagram of an open stomatal pore and label (I) Guard cells, and (II) Chloroplast on it. Mention two functions performed by stomata.

(a) Experiment: Place a small potted plant in a bell jar and seal the jar. Pass carbon dioxide-free air through the plant using a syringe. Observe the plant after some time. Conclusion: The plant will not undergo photosynthesis as it does not receive carbon dioxide. (b) Diagram:  Figure 5.3 (a) Open and (b) closed stomatal pore (I) Guard cells (II) Chloroplast Functions of stomata: 1. Exchange of gases: Stomata allow the exchange of gases between the plant and the atmosphere. 2. Transpiration: Stomata play a crucial role in transpiration, which is the process by which plants release water vapor into the air.