in a limited government the government is limited by law
in a unlimited government the law sets no limits on the actions of a government
tyranny can result in an abuse of power such as the abuse military power against its citizens.
When there is a normal democratic limited government the government can not use force like police or military against protesters or other sorts of opposition. In an unlimited government or a tyranny the government can enforce its will on its citizens and almost nothing can stop it except an uprising or something similar.
Surface of the Earth: Most of the Earth's surface (70%) is covered with water, and the remaining 30% is taken up by the seven continental landmasses. However, underneath the water that fills the oceans, and the dirt and plants that cover the continents, the Earth's surface layer is made of rock.