Which plant tissue carries water up from the roots?

• A. Xylem
• B. Phloem
• C. Cambium
• D. Epidermis

Answer: (A)

Water moves upward through xylem. This vascular tissue is made of hollow, dead cells with thick lignified walls that form continuous tubes from roots to shoots. As leaves transpire, water is pulled up the plant by the cohesion-tension mechanism—the cohesive forces between water molecules and adhesion to the xylem walls create a continuous column that can be drawn upward. Root pressure can help a bit at times, but the main driver is transpiration, and the xylem’s structure supports one-way transport from roots toward the rest of the plant.

Phloem, on the other hand, transports sugars and other nutrients, and can move substances in multiple directions depending on needs. Cambium is a growth tissue that generates new xylem and phloem during secondary growth, and the epidermis is the outer protective layer, not involved in water transport.