How does carbon dioxide enter the leaf?

• A. Through the chloroplasts
• B. Through the roots
• C. Through the thylakoids
• D. Through the vascular system
• E. Through the stomata

Answer: (E)

Verified step by step guidance

1. Understand the structure of a leaf: A leaf is composed of several layers, including the epidermis, mesophyll, and vascular bundles. The epidermis contains small openings called stomata.
2. Learn about stomata: Stomata are tiny pores found on the surface of leaves, primarily on the underside. They are surrounded by guard cells that regulate their opening and closing.
3. Recognize the function of stomata: Stomata play a crucial role in gas exchange, allowing carbon dioxide (CO2) to enter the leaf and oxygen (O2) and water vapor to exit.
4. Identify the process of gas exchange: When stomata are open, CO2 from the atmosphere diffuses into the leaf through these pores. This CO2 is then used in the process of photosynthesis within the chloroplasts.
5. Conclude the pathway of CO2: Carbon dioxide enters the leaf through the stomata, not through chloroplasts, roots, thylakoids, or the vascular system.