US Presidents Trivia: Who is the only President to serve in the army after the conclusion of his Presidency?

Having military experience isn't a prerequisite to becoming President of the United States, but is sure does help win a campaign.  31 of the 43 men to serve as President had some form of military experience, with 12 achieving the rank of general.  The President is the Commander and Chief of the United States and is actually a civilian; as a result, military service ends with (or before) ascension to the Presidency.  However, once in US History, and only once, has a President rejoined the military after serving as President.  So, off of Pocket Trivia: US Presidents - Who is the only President to serve in the army after the conclusion of his Presidency?  Was it:

• George Washington
• Dwight Eisenhower
• Andrew Jackson
• Ulysses Grant

US History Trivia: What is the oldest branch of the U.S. Military?

It's a bit strange to think about, but the five American military branches (Army, Navy, Air Force, Marines and Coast Guard) were not all actually formed at the same time (okay, maybe it's not too strange to think about, at least in terms of the Air Force!).  All branches have different founding dates, but just like everything, one of them is the oldest.  So, off of Pocket Trivia: US History -  What is the oldest branch of the U.S. Military?  Is it:

• Navy
• Army
• Coast Guard
• Marines