Answer:
Federal government.
Step-by-step explanation:
The U.S. federal government may be defined the national government that includes almost five territories, 50 states and federal district. This government includes the executive, judicial and legislative.
This federal form of government is important as it is quite effective and provide proper protection and security than the other government of the country. The states involve in the federal government has different size and do not requires the invasion from the enemies.
Thus, the answer is federal government.