Answer:
Sovereignty - is important because this is what gives a government the right to govern itself without any coercive influence from other governments. Without sovereignty, a government is said to be controlled by external forces outside its own control.
Legitimacy - this is important because is what makes government action seem fair to the people it governs. Without legitimacy, the government may be feared, but no respected, and may be subject to revolt.
Jurisdiction - This is important because every government needs a land to rule. A government cannot really exist without having a place under its jurisdiction, as can be seen by historical examples of governments in exile who had no real power.