What is generally the range of a star's hydrogen burning ...

[olgavictoria]

What is generally the range of a star's hydrogen burning lifetime?
 
  A) from a few million to 50 billion years
  B) from a few hundred thousand to 20 billion years
  C) from 20 billion to 100 billion years
  D) from 2 billion to 15 billion years

Question 2

Why can't any star, no matter how massive, fuse elements heavier than iron?
 
  A) because the nucleons within iron have the least mass possible
  B) because elements heavier than iron have less average mass per nucleon
  C) It could happen, we just have not yet observed a star massive enough to do this.
  D) Actually, this occurs on a regular basis, which explains the great abundance of heavy elements.
  s on a regular basis, which explains the great abundance of heavy

[patma1981]

Answer to Question 1

Answer: A

Answer to Question 2

Answer: A

[olgavictoria]

Excellent

[diana chang]

Gracias!