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: LOW TECH 
Clue: Stone item seen here from the Neolithic, or "New Stone" Age

SOLUTION: arrowhead

PROBLEM: Category: WORLD RELIGION 
Clue: Inti was the sun god prayed to by the ruling family of this South American empire

SOLUTION: incas

PROBLEM: Category: MEDICINE 
Clue: E. Donnall Thomas shared the Nobel Prize for the first transplant of this bone substance between 2 people who weren't twins

SOLUTION:
marrow