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WAEC Biology 2016 Question 22

Question 22

Photosynthesis and Plant Nutrition

The steps below are involved in the testing of a leaf for starch: I. Decolorize leaf II. Dip decolorized leaf in warm water III. Place leaf in boiling water IV. Add iodine solution
The best time to pluck the leaf for the experiment is

  1. A.after being exposed to sunlight.
  2. B.three hours after sunset.
  3. C.before sunrise.
  4. D.six hours after sunset.
Show the answer and explanation

Answer: A (after being exposed to sunlight.)

Explanation

A leaf that has been in sunlight has been photosynthesising and has stored starch, so the test will show a result.