AP BIOLOGY

Detailed explanation-1: -Carbon dioxide and oxygen cannot pass through the cuticle, but move in and out of leaves through openings called stomata (stoma = “hole"). Guard cells control the opening and closing of stomata. When stomata are open to allow gases to cross the leaf surface, the plant loses water vapor to the atmosphere.

Detailed explanation-2: -Carbon dioxide from the air enters the leaf through the stomata.

Detailed explanation-3: -On the underside of leaves and elsewhere, depending on the plant, are tiny openings called stomata-thousands of them per leaf with variations by plant species. Like little castle gates, pairs of cells on the sides of the stomatal pore-known as guard cells-open their central pore to take in the carbon dioxide.

Detailed explanation-4: -Carbon dioxide (CO₂), oxygen (O₂) and water (H₂0) commonly move in or out via the stomata. While gas exchange occurs, carbon (C) stays inside the leaf as a building block for the plant. Often, stomata are open during the day when photosynthesis is taking place and closed at night when it stops.