WAEC - Biology (2016 - No. 12)
The steps below are involved in the testing of a leaf for starch. Study them carefully and answer the question:
I. Decolorize them
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?
after being exposed to sunlight
three hours after sunset
before sunrise
six hours after sunset
Giải thích
The leaf that was in the light turns blue-black, which demonstrates that the leaf has been performing photosynthesis and producing starch.