The diameter of a certain kind of pollen is about 40 microns. How many pollen grains can be connected up to 1 meter?

The diameter of a certain kind of pollen is about 40 microns. How many pollen grains can be connected up to 1 meter?

Because 1 μ M = 10-6 m, the diameter of this kind of pollen is about 40 × 10-6 m, that is 4 × 10-5 m, 1 △ (4 × 10-5) = 2.5 × 104 (grains). A: 2.5 × 104 grains can be connected up to 1 m