Instructions: Given scientific fact as input, generate the question from this fact such that it can be answered from the input.
Input: Within the microsporangium, the microspore mother cell divides by meiosis to give rise to four microspores, each of pollen grain will ultimately form this.
Output:
Within the microsporangium, the microspore mother cell divides by meiosis to give rise to four microspores, each of which will ultimately form this?