The leaf as an organ

你需要知道的

• Leaves are built to collect the three needs of photosynthesis: water, carbon dioxide and light.
• Carbon dioxide enters through stomata, which are mostly on the underside of the leaf.
• Guard cells open and close the stomata, balancing gas exchange against water loss, and many plants close them at night.
• Chloroplasts containing chlorophyll absorb light, and leaf size, shape and waxy cuticle suit the plant's habitat.

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