Leaf Structure and Photosynthesis

Steps:

• Recall that photosynthesis occurs in leaves, requiring CO2 absorption for sugar production.
• Identify leaf layers: epidermis (outer), mesophyll (inner with chloroplasts), vascular tissues (xylem/phloem).
• Match CO2 absorption to cells with stomata access and chloroplasts for gas exchange.
• Confirm mesophyll as site of CO2 fixation in Calvin cycle.

Why B is correct:

• Mesophyll contains palisade and spongy cells with chloroplasts that absorb CO2 through stomata for photosynthesis.

Why the others are wrong:

• A. Cuticle: Waxy protective layer on epidermis that prevents water loss, not gas absorption.
• C. Phloem: Vascular tissue that transports sugars from photosynthesis, not involved in CO2 use.
• D. Xylem: Vascular tissue that conducts water and minerals upward, unrelated to CO2 absorption.

Final answer: B