Describe two different ways that a pollen grain can get to the stigma of a pistil

there are so many examples for that in different areas, like biology experiment carried out in our lab recently.

here's one link:

primary succession occurs in essentially lifeless areas regions in which the soil is incapable of sustaining life as a result of such factors as lava flows, newly formed sand dunes, or rocks left from a retreating glacier. secondary succession occurs