cross pollination

• what are the 4 reasons why self pollination is unlikely to take place

  the stamen and the stigma ripen at different times, the anther is bellow the stigma , genetic/chemical incompatibility and some plants will be unisexuall
• how will the anther being below the stigma mean self pollination cannot take place


  the pollen cannot fall from the anther onto the stigma
• what is meant by genetic/chemical incompatibility in terms of self pollination

  pollen ill be unable to germinate on the stigma of the flower which produced it
• how will some plants being unisexual stop self pollination


  some plants will only have either male or female parts meaning self polliantion is impossible