TASK DEFINITION: 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 consistency, answers should be in all lower cased letters.
PROBLEM: Category: UNIVERSITY SPORTS TEAMS 
Clue: You could say these athletes at UNLV aren't "without a cause"

SOLUTION: the rebels

PROBLEM: Category: ANIMALS 
Clue: Types of this aquatic creature include chimney, sheep's wool, and common bath

SOLUTION: the sponge

PROBLEM: Category: PHYSICAL SCIENCE 
Clue: On Earth, it's the major force responsible for the weight of a body

SOLUTION:
gravity