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Item 15 refers to the following diagram 16. Which of the following is NOT a
which represents part of the nitrogen cycle. characteristic feature of xylem vessels?

(A) No end walls
(B) Cells end to end
(C) Thick cellulose cells walls
(D) No cell contents (hollow)

17. Root pressure, capillarity, cohesion and
adhesion all contribute to

(A) the movement of sucrose along
the phloem
(B) the ascent of water in xylem
vessels
15. Nitrifying bacteria are MOST active at (C) the mass flow of nutrients along
sieve elements
(A) A (D) the loss of water via the leaves
(B) B
(C) C
(D) D

Item 18 refers to the figure below showing an outline of some of the cells from the phloem
of a mango tree.

18. Which of the following correctly identifies the structures numbered I to IV?

I II III IV
(A) Sieve pore sieve tube plasmodesma companion cell
(B) Pasmodesma sieve plate sieve pore sieve tube
(C) Plasmodesma sieve plate sieve pore companion cell
(D) Seve plate sieve pore sieve tube plasmodesma

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02207010/SPEC 2017