instruction:
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.
question:
Category: U.S. PRESIDENTS 
Clue: The last names of 8 different presidents end with this 3-letter combination
answer:
son


question:
Category: ANIMALS 
Clue: Odobenus, the genus name of this animal, comes from the Greek for "one who walks with his teeth"
answer:
walrus


question:
Category: THE SOLAR SYSTEM 
Clue: The 2 planets in our solar system that have atmospheres made up mostly of carbon dioxide
answer:

venus & mars