Which one of the following statements is believed to be true of comets?
A) Their bright, glowing appearance in the night sky is due to frictional heating in Earth's atmosphere.
B) They have highly elliptical orbits around the Sun.
C) They may gain slightly in mass with each orbit around the Sun.
D) They are composed mostly of dense rock particles.

Question

Quizplus · Accepted Answer

Comets are believed to have highly elliptical orbits around the Sun, which causes them to periodically traverse into the inner Solar System, creating their bright, glowing appearance as they are heated by the Sun's radiation. Comets are also composed of ice and dust particles, and may lose some of this material as it sublimates during their orbit. There is no evidence to suggest that they gain mass with each orbit. Comets are not composed mostly of dense rock particles, but instead, are composed mostly of ice and dust particles.

Which One of the Following Statements Is Believed to Be