Oh man. I have 2 guesses. But I think I will go with guess number 2, which is less obvious.

What are American uniforms?

OK, wait: actually I have I have 3 guesses.

What are decryption codes?

Nah... ok ok. I'll guess the obvious one: What are letters negotiating and agreeing to the handover of West point?

Man, it is no wonder I can never finish an exam on time! Sorry for making 3 guesses. It's a disability, don't hate.

theresa <---brain still paralysed from too much cider last night

I think it was the plans for West Point, but I'll take it.

I also think it was Saratoga, not Yorktown, that was damaged at Coral Sea.

The senior Japanese commanders did end up wishing they had committed all six of their big carriers to Midway and believed they would have won if they had.

One report has it that the Japanese gamed the battle ahead of time and their "adversary" commander did what the Americans did, sinking three of the Japanese carriers. They decided to rule out the result because "you knew our battle plan, and they won't." As I titled this category, Intelligence Matters.

#3: General "Wild Bill" Donovan headed this WWII organization, forerunner of the CIA.

OSS (Office of Strategic Services)

"Who was Lavoisier?"

Wasn't he the conservation of mass guy? Also some sort of tax collector for his day job, so was a prime candidate for beheading in the revolution.

I don't even have a guess. He he that is compensation for making 3 on that last one.

Ah, we have another winner, folks! Nice going, donp!

#4: This is the largest U.S. Government intelligence agency. (HINT: It's NOT the CIA.)

Side story: My mom was recruited to work in OSS as a cryptanalyst (Rosie the codebreaker!) though officially in the Navy.

They told her that if she ever told anyone what she was doing she would be shot. She told me after it was declassified in the 90's, but my father was dead by then so I don't think he ever knew.

I'll hold off on #4 for a while.

Greetings, new here....What is NSA?

Welcome! Nicely done!

Now here's the really nasty one, Double Jeopardy, bonus, special commendation:

#5: This contribution from a surprising source, used by the US in WWI and on a much larger scale in WWII, is considered the most unbreakable code ever developed.

Feel free to use Google -- it's still tough even with help, unless you happen to know the story already.