The tail of a comet always points:
A) toward the Sun and disappears at perihelion.
B) toward Earth and never varies.
C) away from the Sun and disappears at perihelion.
D) away from the Sun and becomes longest and brightest at perihelion.
E) in the direction of the comet's motion.
Question 2
What property of Mars is responsible for producing the great heights of its volcanoes?
A) Its cold temperatures allow the magma to freeze faster.
B) Its thick crust can support larger peaks, and lower surface gravity does not pull them down as much as on Earth.
C) Mars has more radioactive material than the Earth.
D) Its higher surface gravity allows higher peaks to form.
E) Its volcanoes are made of sulfur, like Io's.
