List three strategies that a bisexual chasmogamous flower can evolve to prevent self-pollination (autogamy).

(N/A) To prevent self-pollination (autogamy) in bisexual chasmogamous flowers,plants have evolved several outbreeding devices:
$(A)$ Dichogamy: In this mechanism,the maturation of the anther and the stigma occurs at different times. This can be protandry (anthers mature first) or protogyny (stigma matures first),which prevents the pollen from reaching a receptive stigma of the same flower.
$(B)$ Herkogamy: This is a mechanical or spatial arrangement where the male and female reproductive organs are placed in such a way that the pollen from the same flower cannot come into contact with the stigma. This physical barrier ensures cross-pollination,as seen in plants like $Hibiscus$ and $Gloriosa$.
$(C)$ Self-incompatibility (Self-sterility): This is a genetic mechanism where the pollen grains of a flower are unable to germinate on the stigma of the same flower or fail to grow pollen tubes in the style,thereby preventing fertilization,as seen in $Abutilon$.