What is the advantage of a cell being shaped like a sphere and one shaped like a cylinder?

There are basically three types of cell shapes: coccus (spherical), bacillus (rod or cylindrical shaped), and spiral (twisted). Cell size is limited by a cell's surface area to volume ratio. The Shape of a cell determines the function of the cell.

Cells having spherical shapes are best and most advantageous because they have the smallest size that increases the surface-to-volume ratio. The cells with spherical shape experience greater frictional resistance.

Cells having a cylinder or rod-shaped helped the cell to concentrate molecules at specific cellular locales. Cylindrical cells are able to concentrate proteins at different locations in the cell.

i'm thinking (a) to keep sand in place; ////////////

explanation: a sand fence or sandbreak, like a snow fence, is used to force windblown, drifting sand to accumulate in a desired place. sand fences are employed to control erosion, sand dune stabilization, keep sand off roadways, and to recruit new material in desert areas.