What is the difference between xylem and phloem?

Xylem and phloem are a little bit like the blood vessels we have in our body and make up what is called 'vascular bundles' in plants. Xylem are essential for providing water to the plant by transpiration from the roots, while phloem transfer sap, which contains sugars and other molecules, between the leaves and roots by a process called translocation. One difference is that xylem only carry water in one direction (from the roots to the leaves), while phloem can carry sap in two directions. Another difference is that xylem are made from tubes of dead cells strengthened with a molecule called lignin. On the other hand, phloem are made from a column of live cells which transfer sap from one cell to another through pores where each cell touches.