What do xylem and phloem transport?

• A. Xylem transports water and minerals; phloem transports sugars and nutrients.
• B. Xylem transports water; phloem transports carbon dioxide.
• C. Both transport only water.
• D. Phloem is dead at maturity; xylem is living.

Answer: (A)

Xylem and phloem form the plant’s transport system, moving different substances to where they’re needed. Xylem carries water and dissolved minerals from the roots upward through the plant, mainly by the pull of evaporation and cohesion of water in the vessels and tracheids. Phloem, on the other hand, moves sugars produced by photosynthesis from sources like leaves to sinks such as growing tissues and storage organs, using a pressure-driven flow that distributes organic nutrients throughout the plant. Phloem is living tissue, with sieve-tube elements and companion cells working together, while xylem is made of dead, hollow cells that form the water-conducting pipes. Carbon dioxide isn’t transported by these tissues; it’s taken in by leaves for photosynthesis. So the correct description is that xylem moves water and minerals and phloem moves sugars and nutrients. The other options don’t fit because they misstate what each tissue carries or the living status of the tissues.