How are Debian and Ubuntu related?

Related questions

1. Is Debian Linux free?
2. Is Kali Linux Debian?
3. Which is better Debian or Fedora?
4. Is Debian Unix or Linux?
5. Is Ubuntu the same as Debian?
6. Is RedHat based on Debian?
7. Is Debian a Linux distribution?
8. Is Kali Linux a good OS?
9. What is Debian Squeeze?
10. Is Debian or Ubuntu more secure?

Tags

1. #other
2. #stable
3. #model
4. #between
5. #differences
6. #testing
7. #tierd
8. #ubuntu
9. #releases
10. #stability
11. #obvious
12. #distributions
13. #these
14. #regular
15. #different
16. #unstable
17. #three
18. #based
19. #released
20. #debian