Mammals have a transport system for carbon dioxide. Plants absorb carbon dioxide from their surroundings to use in photosynthesis. Explain how a molecule of carbon dioxide from the atmosphere reaches the site of photosynthesis in a leaf.

Diffusion ; down concentration gradient;A lower concentration of carbon dioxide inside leaf / ora; (diffuses) through stoma/ stomata ; (through) (intercellular) air space/(between) spongy mesophyll ; into/reached, palisade, mesophyll/ cell; A into guard cell/ spongy, mesophyll/ cell chloroplast ; AVP ; e.g.dissolve/ diffuse, through cell wall / cell membrane/ cytoplasm