____12. Which part of the comet is the only one that exists when the comet is far from the
Sun?
A. The coma.
B. The dust tail
C. The ion tail
D. The nucleus.
____13. What is the Oort Cloud?
A. A cluster of asteroids.
B. A swarm of comets far from the Sun
C. The cloud that a meteoroid produces in the atmosphere.
D. The same as the coma of the comet.​