29. In what way does the size of a star determine how far down the
set of reactions of Question 26 stellar synthesis will proceed?
What eventually happens to the star if it falls short of synthesis
of iron? What happens eventually if it does synthesize iron in its
30. How far down the set of stellar synthesis reactions will our
own sun go?
31. Where did the heavy elements in our planet (and in the solar
system) come from? Were they made in the interior of our sun?
32. Why is helium so rare on Earth, although common in the universe
as a whole?
33. Why is the nitrogen content of the Earth less than in the entire
universe, whereas the oxygen content is a thousand times greater?
34. Why is the composition of a living organism enriched in carbon
and nitrogen relative to the other elements?