A _____ is a collapsing cloud of gas and dust destined to become a star.
A) protostar
B) protocloud
C) stellar cluster
D) stellar association
Question 2
Which of the following statements is true of protostars?
A) They are luminous red objects.
B) They are smaller than main-sequence stars.
C) They have completely collapsed.
D) They have temperatures that are more than 10,000 K.