question_answer 38)

  Length of pollen tube depends on the distance between (a) pollen grain and upper surface of stigma        (b) pollen grain on upper surface of stigma and ovule (c) pollen grain in anther and upper surface of stigma (d) upper surface of stigma and lower part of style

Answer:

                  (b) Length of pollen tube depends on the distance between pollen grain on upper surface of stigma and ovule. A pollen grain falls on the stigma of the carpel, bursts, open and develops a pollen tube downwards through the style towards the ovule in the ovary.