NEET BIOLOGY

Detailed explanation-1: -Water flows up from the roots, through the trunk and branches, to the leaves, where it is used in photosynthesis. Alongside xylem is another system of tubes called phloem, which transports the glucose formed in photosynthesis into the branches, fruit, trunk and roots of the tree.

Detailed explanation-2: -The mechanism by which sugars are transported through the phloem, from sources to sinks, is called pressure flow. At the sources (usually the leaves), sugar molecules are moved into the sieve elements (phloem cells) through active transport.

Detailed explanation-3: -Y: In phloem the direction of movement of phloem sap is bidirectional. Z: In xylem the movement of water and mineral is unidirectional.

Detailed explanation-4: -The photosynthates from the source are usually translocated to the nearest sink through the phloem sieve tube elements. For example, the highest leaves will send sugars upward to the growing shoot tip, whereas lower leaves will direct sugars downward to the roots.