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WAEC Biology 2011 Question 11

Question 11

Growth and Development

Secondary growth is brought about by the activities of the

  1. A.phellogen and phelloderm.
  2. B.phellogen and procambium.
  3. C.vascular cambium and phelloderm.
  4. D.vascular cambium and phellogen.
Show the answer and explanation

Answer: D (vascular cambium and phellogen.)

Explanation

Secondary thickening comes from two meristems: the vascular cambium (new xylem and phloem) and the phellogen or cork cambium (new bark).