A scientist claims that all red main-sequence stars are 1 billion years old. Which of the following, if true, would prove that this claim is false?
A) The discovery of a red main-sequence star in a star cluster where the main sequence turnoff is about that of the Sun
B) The discovery of a red main-sequence star in a star cluster where all the other stars are red giants or red supergiants
C) Stellar evolution theory predicts that the main-sequence lifetime of red stars can be as long as 100 billion years.
D) The minimum lifespan of a red main-sequence star is estimated to be 10 billion years.
Question 2
Most of the mass of the Milky Way is located in the halo of the galaxy in the form of dark matter.
Indicate whether the statement is true or false
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