Question

a scientist observes that the spectra of many stars in a galaxy are shifting toward the red end of the spectrum. which inference can be made based on this finding?\
\
\bigcirc the size of the galaxy is shrinking.\
\bigcirc the galaxy is moving toward the scientist.\
\bigcirc the galaxy is moving away from the scientist.\
\bigcirc the size of the galaxy is increasing.

Explanation:

The redshift (shift toward red end of spectrum) occurs when an object is moving away from the observer (Doppler effect in astronomy). A blue shift would be toward, but here it's red shift, so the galaxy is moving away. The other options: shrinking or size increasing aren't directly related to spectral shift direction; moving toward would cause blue shift, not red.

Answer:

The galaxy is moving away from the scientist.