1. cálculo   astronomy   biology   geology   calculus   Hint Half-n-half Clue   2. geografía   geography   philosophy   calculus   geometry   Half-n-half Clue   3. historia   philosophy   geography   astronomy   history   Half-n-half Clue   4. geología   geology   physics   zoology   geography   Half-n-half Clue   5. zoología   zoology   trigonometry   geography   psychology   Half-n-half Clue   6. geometría   history   trigonometry   psychology   geometry   Half-n-half Clue   7. filosofía   geology   physics   philosophy   geography   Half-n-half Clue