10. social

11. environmentalists 
12. pollutants
13. occurrence 
14. spectacular
15. natural
16.correspondence 
17. disconnected
18. advantageous 
19. addicted
20. inventions

UNIT 11:

1. invention                      

2. discoveries                

3. realistic                        

4. economic

5. scientific                       

6. development                

7. technological                

8. technologically

9. precision                      

10. supporters

11. invention                    

12. medical                       

13. electricity                   

14. scientists

15. technician                   

16. scientists                     

17. improvement              

18. inventor

19. beneficial                    

20. transformation

UNIT 12:

1. accommodations          

2. experienced                  

3. spacesuit