Across
- 2. piping
- 4. steel
- 6. car
- 7. heart valve
- 9. cheeseburger
- 10. bottled water
- 13. plastic
- 15. use of steel and iron
- 16. wood
- 17. plastic
- 18. 450-1400AD
- 19. 2300BC-700BC
- 20. rebirth
Down
- 1. liquids
- 3. stone tools
- 5. development of manufacturing and transportation
- 8. the processing and exchange of information
- 11. wool socks
- 12. consumable goods
- 14. carbon fiber