More massive stars are _________ luminous and __________ than less massive stars, thus they pulsate _____________.
a. less, smaller, faster b. more, larger, slower
c. more, larger, slower d. less, smaller, faster
Question 2
The creation of ________ require(s) that a young hot star (T 25,000 K) be relatively nearby.
a. emission nebulae
b. HI regions
c. molecular clouds
d. the cool gas of the interstellar medium
e. 21-cm radiation