AP BIOLOGY

Detailed explanation-1: -Xylem tissue consists of a variety of specialized, water-conducting cells known as tracheary elements.

Detailed explanation-2: -Continuous transpiration occurring in all of the leaves of a plant creates a negative pressure in the water column (xylem). This exerts an upward pull on the water column, called transpiration pull. And thus, the water present in the xylem column transports up to the tip of the stem, leaves, etc.

Detailed explanation-3: -The xylem transports water and minerals from the roots to the leaves while the phloem moves food substances from leaves to the rest of the plant.

Detailed explanation-4: -Mature xylem tissues are composed of three main cell types: xylem tracheary (vessel) elements, xylary fibres, and xylem parenchyma cells (Fig. 1).