The answer is 48000 because every flower of crotolaria would have 10 stamens, 10 stamens would have 10 anthers, 10 anthers would have 40 microsporangia, each microsporangia has 30 30 microspore mother cells so, 40 microsporangia would have 1200 microspore mother cells. Each microspore would produce 4 pollen grains, taking the number of pollen grains produced by a flower to 1200 X 4 = 4800. Since there are 10 flowers the answer would be 4800 X 10 = 48000 pollen grains.