A Team of Astronomers Takes Spectra of Thousands of Different

Multiple Choice

A team of astronomers takes spectra of thousands of different stars in different parts of the sky. The spectra show significant differences. The main reason the spectra of the stars do not all look alike is that the stars

A) are located in many different regions of the Milky Way
B) have different temperatures
C) are made of significantly different elements
D) sometimes have atmospheres and sometimes do not
E) change their spectra as they age, and so young stars have very different spectra from older ones