You will be given a trivia clue, and the category it belongs to. You should answer with the best answer that belongs in the category and is described by the clue. For simplicity, answers should be in all lower cased letters.

Category: TRANSPORTATION 
Clue: An aircraft that can take off & touch down on water or land is called this, like a class of animals
amphibious

Category: FICTIONAL BATTLES & WARS 
Clue: Juan Rico joins the mobile infantry to fight in the war against the invading alien "bugs" in this Heinlein novel
starship troopers

Category: GOVERNMENT & POLITICS 
Clue: The FHA, an agency of this cabinet department, provides mortgage insurance for homeowners' loans

hud