The following 10 questions refer to the numbered stars in the diagram below. Please enter one star number in response to each question below. The same star number may be used more than once

21. Which star has the highest luminosity

22. Which star has a main sequence lifetime of about 1 billion years

23. Which star is fusing Helium as its primary energy source

24. Which star has the longest hydrogen burning lifetime

25. Which star most likely has ionized hydrogen in its atmosphere?

26. Which star has the lowest mass?

27. Which star has a mass of around 0.5 solar masses?

28. Which star is supported by electron degeneracy?

29. Which star has a main sequence lifetime of around 10 billion years?

30. Which star has strong hydrogen absorption lines in its spectrum?