Why is it important that the spongy mesophyll in plant leaves has gaps or air spaces in its layers?

• A. To provide structural support to the leaf.
• B. To increase the surface area for light absorption.
• C. To store excess water for the plant.
• D. To facilitate the exchange of gases necessary for photosynthesis.

Answer: (D)

Verified step by step guidance

1. Understand the role of spongy mesophyll in plant leaves: The spongy mesophyll is a layer of cells found in plant leaves, primarily involved in gas exchange.
2. Recognize the importance of gas exchange: Photosynthesis requires carbon dioxide ( $\mathrm{CO}2$ ) to produce glucose and oxygen ( $O2$ ) as a byproduct.
3. Identify the function of air spaces: The gaps or air spaces in the spongy mesophyll allow for efficient movement of gases, facilitating the exchange of $\mathrm{CO}2$ and $O2$ .
4. Consider the structural arrangement: The loose arrangement of cells in the spongy mesophyll increases the surface area for gas exchange, enhancing the plant's ability to perform photosynthesis.
5. Conclude the importance: The presence of air spaces in the spongy mesophyll is crucial for the plant's survival, as it ensures that the necessary gases for photosynthesis are readily available.