Yanis,
Sorry for the delay.
Looks like your talking about the definition of a sphere. Those parameters define the sphere, and the extent it is complete or whole. You can create just a half sphere or partial sphere, and choose how coarse or refined the definition is by changing those parameters. It is helpful to change the viewing to a wireframe surface to see the effect of each of the parameters.
Let me know if you have other questions.
Best,
DH