Biology 9700 · AS & A Level · Structure of transport tissues

Structure of transport tissues — practice question

Which statement is correct about phloem sieve tube elements?

  • ACompanion cells provide structural support to the phloem sieve tube elements.
  • BLignified walls of phloem sieve tube elements prevent transport of mineral salts by mass flow.
  • CPhloem sieve tube elements become narrower as movement of sucrose occurs.
  • DPlasmodesmata allow movement of water and solutes across cell walls of phloem sieve tube elements.

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