Answer : 4. "transfer of pollen from anther to stigma"
Explanation :

Answer: D) transfer of pollen from anther to stigma Explanation: Pollination is when pollen grains from an anther, the male portion of a flower, are transferred to a female part of the flower, known as the stigma. In order for pollination to be successful, the pollen grains transferred must be from a flower of the same species.   After the pollen grains land on the stigma, they create a pollen tube through the length of the style or stalk connecting the stigma and ovary. Once the pollen tube is complete, the pollen grain will send sperm cells from the grain down to the ovary. When the sperm cells reach the ovary and the egg cells, fertilization will occur, which will result in the formation of the seed. The seed will then be released from the parent plant and will be able to grow into a plant and continue the reproductive cycle using the method of pollination.