Why is it important that a plant's phloem extends into its leaves?
The phloem allows carbon dioxide to enter the leaf and oxygen to escape it during photosynthesis.
The phloem brings water and nutrients up from the roots, so that photosynthesis can take place.
The phloem collects the sugars made during photosynthesis and carries them around the plant.
The phloem protects the leaf from sun damage and excess water loss on hot, sunny days.