What is the process of transferring pollen grains to the stigma of a flower called?

The process of transferring pollen grains to the stigma of a flower is known as pollination. This is a crucial step in the reproductive cycle of flowering plants, as it allows for fertilization to occur. During pollination, pollen, which contains male gametes, is transferred from the male part of the flower (the anther) to the female part (the stigma). Once the pollen reaches the stigma, it can germinate and grow a pollen tube down to the ovary, where fertilization can take place, leading to the formation of seeds.

In the context of the other options, fertilization refers to the actual fusion of male and female gametes which occurs after pollination. Photosynthesis is the process by which plants convert light energy into chemical energy, and germination refers to the process by which seeds develop into new plants. Therefore, pollination is distinctly focused on the transfer of pollen and is a fundamental event leading to seed development.