Which of the following is an effective adaptation for better gas exchange in plants ?

Options

A. Presence of multiple epidermis
B. Presence of hair on the lower epidermis
C. Presence of waxy cuticle covering the epidermis of the leaves
D. The location of the stomata primarily on the lower surface of the leaf, the side turned away from the direct sun rays

Explanation

To determine which adaptation is effective for better gas exchange in plants, we will analyze each of the provided options step by step.

### Step-by-Step Solution:

1. **Understanding Gas Exchange in Plants**:
- Gas exchange in plants primarily occurs through small openings called stomata. These pores allow for the exchange of gases such as carbon dioxide (CO2) and oxygen (O2) during photosynthesis and respiration.

2. **Evaluating the Options**:
- **Option 1: Presence of Multiple Epidermis**:
- The presence of multiple layers of epidermis can hinder gas exchange as it creates an additional barrier for gases to diffuse through. Therefore, this option is not effective for better gas exchange.
- **Option 2: Presence of Hair on the Epidermis**:
- Hair on the epidermis can trap moisture and reduce water loss, but it does not facilitate gas exchange. This adaptation is more about reducing transpiration rather than enhancing gas exchange. Hence, this option is also incorrect.
- **Option 3: Presence of Waxy Cuticle Covering the Epidermis**:
- A waxy cuticle is designed to minimize water loss through evaporation. While it protects the plant, it does not aid in gas exchange. Therefore, this option is not effective for better gas exchange.
- **Option 4: Location of Stomata Primarily on the Lower Surface of the Leaf**:
- The stomata are usually located on the lower surface of leaves, which is shaded from direct sunlight. This positioning helps to reduce water loss through transpiration while still allowing for gas exchange. This adaptation is effective for better gas exchange.

3. **Conclusion**:
- After evaluating all options, the most effective adaptation for better gas exchange in plants is **Option 4: Location of Stomata Primarily on the Lower Surface of the Leaf**.

### Final Answer:
**The correct answer is Option 4: Location of Stomata Primarily on the Lower Surface of the Leaf.**

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