Examlex
Cygnus X- 1 was discovered because it is a(n) source in a(n) system.
Q27: Stars evolve along the main sequence.
Q27: Elements heavier than iron are formed mainly
Q51: Fewer than 100 stars lie within 5
Q73: Shapley found that globular clusters are only
Q75: While more massive than most of its
Q106: Globular cluster stars are _ in heavy
Q110: Which statement about the stages of starbirth
Q146: Almost all properties of other stars are
Q151: The least massive red main- sequence stars
Q159: The longer the period of pulsation for