Prefixes dis- and de-

1. discuss

2. deduct

3. dismissed

4. develop

5. disease

6. discount

7. disturb

8. disappointing

9. details

10. demand

11. determined

12. depressed

13. defense

14. discouraged

15. disadvantage

16. demonstrated

17. defeat

18. descent

19. disappear

20. disconnect

Extra Credit Word: a. Iditarod  b. Alaska  c. diphtheria