Thin and elastic walls of guard cells are

Options

A. Inner and lateral
B. Inner
C. Outer
D. Outer and lateral

Answer

To solve the question regarding the thin and elastic walls of guard cells, we can follow these steps:

### Step-by-Step Solution:

1. **Understanding Guard Cells**:
- Guard cells are specialized cells that form the stomata, which are small openings on the surface of leaves. They play a crucial role in regulating gas exchange and transpiration in plants.

2. **Structure of Guard Cells**:
- Each guard cell has two types of walls: the inner walls and the outer walls.
- The inner walls of the guard cells are thick and inelastic, which helps maintain the shape of the stomata when they open and close.

3. **Identifying the Thin and Elastic Walls**:
- The outer walls of the guard cells are thin and elastic. This elasticity allows the guard cells to change shape, which is essential for the opening and closing of the stomata.

4. **Analyzing the Options**:
- The question provides four options regarding which walls of the guard cells are thin and elastic:
- A) Inner and lateral
- B) Inner
- C) Outer
- D) Outer and lateral
- Based on our understanding, the outer walls are indeed thin and elastic.

5. **Selecting the Correct Answer**:
- The correct answer is option D: "Outer and lateral walls" are thin and elastic.

### Final Answer:
The thin and elastic walls of guard cells are the outer and lateral walls (Option D).

---