[Campbell Biology P.814] Which of the following statements accurately describes sieve-tube e... | Practice Question

Which of the following statements accurately describes sieve-tube elements in angiosperm phloem?

  • A: They are nonconducting cells that support sieve cells.
  • B: They lack a nucleus and ribosomes at functional maturity but are alive.
  • C: Their end walls have pits that allow water to flow freely.
  • D: They are dead and lignified at functional maturity.

Explanation

The text states that sieve-tube elements, though alive at functional maturity, 'lack a nucleus, ribosomes, a distinct vacuole, and cytoskeletal elements.' This reduction in cell contents facilitates nutrient transport.