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: -Most plants use a pore-like structure called stomata (singular: stoma) on the undersides of leaves to absorb carbon dioxide from the air. The carbon dioxide is used to build sugars, which can be used by the plant as energy or for incorporation into the plants’ fibrous cell walls.

Detailed explanation-3: -Answer: (a) (ii) Stomata, carbon dioxide from the air is taken in through the tiny pores present on the surface of leaves. Such pores are called stomata.

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.

Detailed explanation-5: -Natural sources of carbon dioxide include most animals, which exhale carbon dioxide as a waste product. Human activities that lead to carbon dioxide emissions come primarily from energy production, including burning coal, oil, or natural gas.