Here's why:

* Phloem: This is the vascular tissue responsible for transporting sugars (like glucose) produced during photosynthesis from the leaves to other parts of the plant, such as the roots, stem, and flowers.

* Xylem: This is the other type of vascular tissue in plants, and it's responsible for transporting water and dissolved minerals from the roots up to the rest of the plant.

So, while both xylem and phloem are important for plant transport, it's the phloem that carries the glucose.