Where is the xylem located in the vascular bundle? What is the function of the tracheid cells? Vessel elements?

Xylem is present adaxial with the phloem being abaxial.

In the stem or root, the xylem is closer to the center of the stem or the root.

Tracheid cells - serve as a support and for the upward conduction of water and dissolved minerals.

Vessel elements are responsible for the ascent of sap from roots to leaves and to the tip of the plants.