AP BIOLOGY

Detailed explanation-1: -Xylem cells constitute the major part of a mature woody stem or root. They are stacked end to end in the center of the plant, forming a vertical column that conducts water and minerals absorbed by the roots upward through the stem to the leaves.

Detailed explanation-2: -The xylem and the phloem make up the vascular systems found contiguously in the roots, stems (Fig. 1-3), and leaves of plants. In a tree trunk the phloem constitutes a layer of the bark and the xylem constitutes almost all of the wood. The xylem provides structural support for land plants.

Detailed explanation-3: -In roots and stem, the xylem tissue is found on the inside – however, in leaves, xylem is found above phloem tissue.