Which of the following is not evidence of the existence of an interstellar medium?
A) extinction
B) narrow calcium lines in the spectra of O and B stars
C) reddening
D) dark clouds
E) molecular bands in the spectra of cool stars

Question

Quizplus · Accepted Answer

Molecular bands in the spectra of cool stars are related to the composition and temperature of the stars themselves, not the interstellar medium. The other options are phenomena or observations that indicate the presence of material between stars.

Which of the Following Is Not Evidence of the Existence