Assetion: The stmatal pore, guard cells and the surrounding subsidiary cells are tohether called stomatal aperture.
Reason: The outer walls of guard cells (alway from stomatal pore) are highly thickened and the inner walls (towards the stomatal pore ) are thin

Explanation

**Step-by-Step Solution:**

1. **Understanding the Assertion:**
- The assertion states that the stomatal pore, guard cells, and the surrounding subsidiary cells are collectively referred to as the stomatal apparatus.
- This statement is true. The stomatal apparatus is indeed composed of these components, which work together to regulate gas exchange in plants.

2. **Analyzing the Reason:**
- The reason provided claims that the outer walls of guard cells are highly thickened while the inner walls (facing the stomatal pore) are thin.
- This statement is false. In reality, the outer walls of guard cells are thinner, and the inner walls are thicker. This structural difference helps in the opening and closing of the stomatal pore.

3. **Conclusion:**
- Since the assertion is true and the reason is false, we can conclude that the assertion is correct, but the reason does not correctly explain the assertion.

4. **Final Answer:**
- The correct option is that the assertion is true, but the reason is false.

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