An H II region signals the presence of:
A) newly formed stars
B) young stars
C) ionized hydrogen gas
D) O- and B-type stars
E) all of the above

Question

Quizplus · Accepted Answer

An H II region is a large region of ionized hydrogen gas that is excited by ultraviolet radiation from newly formed, young, hot stars, typically O-type and B-type stars. Therefore, the correct answer is all of the above, as the presence of an H II region indicates the presence of all of these features.

An H II Region Signals the Presence Of