No, but many are registered as trademarks.
Not unless it bears military markings the branch of service and of rank AND you are holding yourself out to be (impersonating) a member of the military. If you strip the rank insignias off the basic camouflage clothing you are not committing any offense by wearing them.
Army Regulations booklet 670-1 Wear and Apperance of Uniforms and Insignia
Yes, the Air Force is a part of a branch in the Military.
the marine corps sure are a military branch.
executive branch
It is most critical for our military to have, Men and women can both serve their country in each branch of the military.
Department of Defense, which is part of the Executive branch
No, the oldest military branch was the Continental Army founded by George Washington.
The Legislative branch
no
Navy