Inside the lower epidermal layer in the green leaves, there is the spongy layer. The spongy layer made of loosely packed cells with many air cavities. The air cavities are engaged in gaseous exchange between different areas of the leaf. The gases enter in the cells through stomata present in the epidermis. Stomata opens in the air cavities. The cells in the spongy layer have very few chloroplasts and are not responsible for photosynthesis.