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 simplicity, answers should be in all lower cased letters.
PROBLEM: Category: ADD A LETTER 
Clue: Adding this letter to heritage gives you a nice, secluded retreat

SOLUTION: m

PROBLEM: Category: MYTHOLOGY 
Clue: This Norse god known for his great strength was a protector of peasants & farmers

SOLUTION: thor

PROBLEM: Category: BILLIONS & BILLIONS 
Clue: To the nearest billion, the world's population

SOLUTION:
seven billion