How does spectroscopy provide evidence for the big bang theory?
A: The red shift shows that galaxies are moving away from each other.

B. The intensities of peaks show that galaxies are moving toward each other.

C. The intensities of peaks show that galaxies are moving away from each other.

D. The red shift shows that galaxies are moving toward each other.

It is A: The redshift shows that galaxies are moving away from each other.

Explanation:

The motion of stellar objects can be determined by looking at their spectrum. Because of the Doppler effect, objects moving towards us are blueshifted, and objects moving away are redshifted. The wavelength of redshifted light is longer, appearing redder than the source. Conversely, the wavelength of blueshifted light is shorter, appearing bluer than the source light.