Pollen tube growth is one of the most fascinating—and essential—phenomena in the life cycle of flowering plants. After a compatible interaction between pollen grains and the stigma surface, the pollen germinates and forms the pollen tube, which grows through the stigma, style, and transmitting tract to deliver the sperm cells to the ovule."
2) Although pollens of many species germinate in simple aqueous media, stigmas do not provide satisfactory sites for the germination of most foreign pollen... Stigmas not only provide the proper conditions for the germination of pollen from their particular species, they actively inhibit the germination of pollen of many unrelated species.
Spectral analysis proposes that there is no hydrogen fusion roughly
speaking. They are hot since they are very thick. So if you are a convinced
high density and temperature and still not doing synthesis, you must be small.
Also, stellar evolution models are founded on the observation of planetary
nebulae, where stars have shed most of their mass after being red giants. The
physics designates a small, hot, central remainder.
i think it is called the nuclear envelope, but I am not sure...
Hope this helped :)
The answer would be A. Im sorry if its wrong