Spectra of stars often show narrow absorption lines from ...

[formula1]

Spectra of stars often show narrow absorption lines from interstellar matter. What type of interstellar matter produces these?
 
  A) dust
  B) neutral gas
  C) ionized gas
  D) molecules
  E) All of the above.

Question 2

Einstein's ________ is a candidate for the dark energy that would be a repulsive force that may exist throughout space, and accelerate the expansion of the universe.
 
  Fill in the blank(s) with correct word

[bdobbins]

Answer to Question 1

B

Answer to Question 2

cosmological constant

[formula1]

Thanks for the timely response, appreciate it

[triiciiaa]

Excellent