(i) It is the transfer of pollen grains from the anther to the stigma of a flower.
(ii) It is achieved by agents like wind,water or animals.
(iii) It leads to fertilization.
(iv) It is an external process.
(i) It is the fusion of male gamete with female gamete (egg).
(ii) It is achieved by the growth of pollen tube so that the male gamete reaches the female-germ" cells. (iii) It leads to formation of seeds.
(iv) It is an internal process.