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: 12-LETTER WORDS 
Clue: Meaning a beginning, it's also a school graduation ceremony

SOLUTION: commencement

PROBLEM: Category: BETTER KNOWN AS.... 
Clue: Singer Helen Folasade Adu

SOLUTION: sade

PROBLEM: Category: FLORA & FAUNA 
Clue: A variety of this endangered mammal is seen here

SOLUTION:
manatee