Why do we think the first generation of stars would be different from stars born today?
A) Without heavy elements, the clouds could not reach as low a temperature as today and had to be more massive to collapse.
B) Without heavy elements, the nuclear reactions at the center of the stars would be very different.
C) Without heavy elements, there was no dust in the clouds and they collapsed faster.
D) The Universe was much denser when the first stars were born.
E) There were no galaxies when the first stars were born.
Answer: A