Question

what are the 3 main branches of the U.S. military

Answer 1

1. The Army - The Department of US Army
2. The Air Force - The Department of US Air Force
3. The Navy - The Department of Navy
4. The Marines - The Department of Navy, Office of the USMC
5. The Coast Guard - The US Coast Guard, Department of Homeland Security

Answer 2

Legislative, Executive, and Judicial.

Answer 3

You asked for the U.S. Military. The Legislative, Executive, And Judicial are the branches of government. That's why I gave you the five U.S. Military branches cause' that's what you asked for.