Answer in one or two word:
Mention one condition in which the stomatal opening gets closed.

Explanation

**Step-by-Step Solution:**

1. **Understand the Function of Stomata:** Stomata are small openings on the surface of leaves that allow for gas exchange (CO2 in and O2 out) and transpiration (water vapor loss).

2. **Identify the Role of Guard Cells:** Each stoma is surrounded by a pair of guard cells that control its opening and closing. The turgidity of these guard cells determines whether the stomata are open or closed.

3. **Recognize Conditions Affecting Stomatal Opening:** Stomatal opening and closing are influenced by various environmental factors, such as light, humidity, water availability, and temperature.

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