AP BIOLOGY

Detailed explanation-1: -The xylem and phloem are distributed differently in roots and stems. In the root, the xylem forms a central column, forming a solid support. The phloem is towards the centre, outside the xylem. In the stem, the transport tissues of the xylem and phloem are grouped into vascular bundles .

Detailed explanation-2: -Xylem and phloem vessels are grouped together within the plant stem and form vascular bundles. Sclerenchyma fibres are also found within vascular bundles and provide support to the stem. Within the plant stem, xylem vessels are found right on the inside.

Detailed explanation-3: -A vascular bundle is a part of the transport system in vascular plants. The transport itself happens in the stem, which exists in two forms: xylem and phloem. Both these tissues are present in a vascular bundle, which in addition will include supporting and protective tissues.

Detailed explanation-4: -In stems and roots, the xylem typically lies closer to the interior of the stem with phloem towards the exterior of the stem. In the stems of some Asterales dicots, there may be phloem located inwardly from the xylem as well. Between the xylem and phloem is a meristem called the vascular cambium.