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: GENERAL SCIENCE 
Clue: A horse's hooves are made up of this protein, the same protein found in your fingernails
keratin

Category: THE U.S. SENATE 
Clue: Generally the Senate ends the day by doing this, rather than adjourning
recessing

Category: SCI. ABBREV. 
Clue: The "T" in TSH stands for this gland (the "SH" if for stimulating hormone)

the thyroid