The function of leaves is to make food in photosynthesis. The amino acids produced are used to provide energy when respired, for the growth and reproduction.
Organic molecules are transported from the leaves to the parts of the plant that need phloem.
Phloem vessels are made from cells-joined end-to-end unlike xylem they are living cells that keep some of their cell contents such as cytoplasm.
structural feature --------> how it improves transport