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JAMB Biology 2004 Question 19

Question 19

Cell and Its Environment

The opening of the stoma is controlled by the

  1. A.presence of a pore
  2. B.increase in solute concentration in the guard cells
  3. C.presence of guard cells
  4. D.decrease in solute concentration in the guard cells
Show the answer and explanation

Answer: B (increase in solute concentration in the guard cells)

Explanation

When solutes build up in the guard cells, water enters them by osmosis. The guard cells swell and curve apart, opening the stoma.