Question

(i) Pluck the leaf to be experimented

(ii) Cover a portion of leaf on both sides by using strips of black paper

(iii) Keep the plant in dark place for three days to destarch its leaves.

(iv) Test the experimental leaf the the presence of starch

(v) Expose the plant to sunlight for four hours

(vi) Remove the black paper strip from the leaf

Given in the box are steps written randomly for the experiment to show that light is essential for photosynthesis. Which of the following sequences of steps is to be followed by the successful run of the experiment?

• A. (i), (iii), (ii) (iv), (v), (vi)
• B. (ii), (i), (v), (vi), (iii), (iv)
• C. (iii), (ii), (v), (i), (vi), (iv)
• D. (v), (ii), (i), (iii), (iv), (vi)

Answer 1

The correct option is C (iii), (ii), (v), (i), (vi), (iv)

The starch in the leaves is eliminated by keeping the plant in a dark place for 3 days. A leaf is selected and covered with a black strip on both sides. The plant is kept in sunlight for 4 hours. The experimental leaf is plucked and the strip is removed from it to perform the starch test. It is found that he leaf covered with black paper will turn brown and the part of the exposed leaf will turn blue-black. This result proves that starch is formed in the leaf where sunlight is available and is not formed in absence sunlight. Thus the correct answer is option C.