The drought alone did not cause the dust bowl. it was combination of several things, the drought and

They began tearing down and deforesting the land so the soil began to erode and thus making it easier to blow away and less likely for the crops to grow.

This post might have the info you need:

Cell division is important to single celled organisms because it allows the cells to reproduce. through cell division, cells make exact copies of themselves. when single celled organisms go through cell division, they make exact copies of themselves which is how they reproduce.