There is a basic difference, because mass is the actual amount of material contained in a body and is measured in kg, gm, etc. Whereas weight is the force exerted by the gravity on that object mg.
The cell that has the nucleus is eukaryotic and the cell that doesn't have a nucleus is eukaryotic
hope it helps

Basically, there is a root. This root makes cells. Those cells die and multiply making your nail longer.