Please answer in paragraph form. Thanks
What is a pollen grain? What role has it played in helping plants colonize dry land?
A pollen grain is a male gametophyte. It is a haploid structure and consists of 3 cells in flowering plants. Two of these cells are sperm cells and, following fertilization, these are carried by a pollen tube to the female gametophyte within the ovule of the flower (note that the process is a little different in non-flowering seed plants).
The pollen tube means that seed plants are no longer dependant on water for fertilization. In the 'lower' land plants (such as mosses) the sperm are flagellated and must swim to the female structures.
Reply:Pollen grain - a structure produced by plants, containing the male gamete to be used in reproduction. The gamete is covered by protective layers which perform there role until the pollen grain is capable of fertilising when reaching the female stigma.
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