Which of the following,above all else,outlines the spiral arms of a spiral galaxy?
A) The jets that are emitted from the supermassive black hole at the core
B) Old,well-established red stars
C) Globular clusters in their orbits around the galactic nucleus
D) Young stars and associated emission nebulae

Question

Quizplus · Accepted Answer

Young stars and associated emission nebulae outline the spiral arms of a spiral galaxy. These stars are formed from the gravitational collapse of gas and dust in the arms and their radiation ionizes the surrounding gas, creating the bright emission nebulae that highlight the arms.

Which of the Following,above All Else,outlines the Spiral Arms of a Spiral