A chemical used to test starch. 

In the diagram drawn alongside
(i) Label the parts a, b and c.
(ii) In which part does the light reaction occur?
iii) Name the part which the dark phase of photosynthesis occur in. 

In a T.S. of a leaf given,
(i) Label the parts a, b, c, d, and e.
(ii) What is the role of b?
(iii) What role does part 'e' play?
(iv) Name the gas that will diffuse during the day in the direction of the arrow in f and in g.