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Experiments conducted to prove the formation of starch in plants

Both the plan...

Question

Both the plants 'A' and 'B' were kept in sunlight after watering. The part of the leaf of plant 'B' which was inserted in the glass bottle containing KOH(Potassium hydroxide) did not turn blue in the iodine test/ starch test, indicating the absence of starch. The part of the leaf outside the bottle turns blue in the said test. Photosynthesis didn't occur in that part of the leaf due to the non-availability of _________.

A

Sunlight

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B

Chlorophyll

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C

C O_{2}

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D

Water

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Solution

The correct option is C $C O_{2}$
Here, this experiment was done to check the importance of carbon dioxide in photosynthesis. The carbon dioxide is reduced to formed carbohydrate i.e starch.
The part of the leaf tested negative because the KOH absorbs the CO₂ present in the surrounding and as a result, there is no photosynthesis.
So, the correct option is 'CO₂'

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Why is the leaf boiled in water and alcohol before testing for the presence of starch?

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Experiments conducted to prove the formation of starch in plants

Standard VIII Biology

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