1. Zoologie   geology   zoology   biology   philosophy   Hint Half-n-half Clue   2. Philosophie   philosophy   astronomy   calculus   physics   Half-n-half Clue   3. Geologie   geology   philosophy   physics   trigonometry   Half-n-half Clue   4. Erdkunde   geography   algebra   zoology   history   Half-n-half Clue   5. Trigonometrie   biology   trigonometry   chemistry   algebra   Half-n-half Clue   6. Chemie   history   chemistry   biology   botany   Half-n-half Clue   7. Geometrie   zoology   geometry   history   chemistry   Half-n-half Clue