SUMMARY
The primary functions of leaves are photosynthesis and transpiration. Photosynthesis is the biological process that converts radiant energy into the chemical energy of carbohydrate molecules. Transpiration is the loss of water vapor by evaporation from aerial plant parts.

The leaf is composed of two layers of epidermis; either one layer of mesophyll or differentiated palisade and spongy tissues; and xylem and phloem. All of these tissues optimize leaf functions. The lower epidermis contains stoma, which regulate the gas exchange that is key to photosynthesis and transpiration.

Activity
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