AP BIOLOGY

Detailed explanation-1: -The xylem moves water and solutes, from the roots to the leaves in a process known as transpiration and its flow is unidirectional. The phloem moves glucose and amino acids from the leaves all around the plant, in a process known as translocation and its flow is bidirectional.

Detailed explanation-2: -The transport of water in the xylem takes place only from the roots to the leaves. Therefore, the movement of water and nutrients in the xylem is unidirectional.

Detailed explanation-3: -Translocation of water and minerals in xylem depends on the transpirational pull and root pressure. Therefore, it is unidirectional due to transpiration pull being developed from roots to leaves. Translocation in phloem is bi-directional: Translocation of food in phloem depends on the source and sink relationship.

Detailed explanation-4: -Phloem transport is bidirectional because sucrose gets accumulated in the phloem tissue and absorbs water creating a high turgor pressure.