What can trigger the gravitational collapse of an interstellar gas cloud?
A) a decrease in temperature
B) an increase in density
C) a rise in temperature
D) A and B
E) A and C
Question 2
Volcanism is more likely on a planet that
A) doesn't have an atmosphere or oceans.
B) has high internal temperatures.
C) is closer to the Sun.
D) is struck often by meteors and solar system debris.