Question

define cross and self pollination..?

Answer 1

Self-pollination - transfer of pollen from the anther to the stigma of the same flower, or to another flower of the same plant.
Cross-pollination - transfer of pollen from the anther of a flower to the stigma of a flower on a different plant of the same species

Answer 2

Self pollination - In this process, pollen lands on the stigma of the same flower or of a different flower of same plant.
Cross pollination - In this case, pollen lands on the stigma of a flower borne on a different plant of the same kind.