Which of the following paraphrases hubble law?
select one:
a. the greater the distance to a galaxy, the greater its redshift.
b. the more distant a galaxy is, the younger it appears.
c. the older the galaxy appears to us, the more luminous it is.
d. the faster the galaxy spins, the more massive and luminous it is.
e. the greater the distance to a galaxy, the fainter it is.

When we talk about the visible electromagnetic spectrum, we know it starts in violet-blue and ends in red.  

Now, in this context the astronomer Edwin Powell Hubble observed several celestial bodies, and when obtaining the spectra of distant galaxies he observed the spectral lines were displaced towards the red (red shift), whereas the nearby stars showed a spectrum displaced to the blue.  

From there, Hubble deduced that the farther the galaxy is, the more redshifted it is in its spectrum, and noted that all galaxies are "moving away from each other with a speed that increases with distance", and enunciated the now called Hubble–Lemaître Law.

This means in the past the distance between two galaxies was smaller than at present, being this the proof that the universe is expanding (like a balloon expands when it is filled with air or another gas).  

However, at this poitn it is important to state clear that the redshift is not produced by the relative movement of the galaxies with each other. This effect is in fact, due to the own expansion of the space among the galaxies.

answer; /// i believe that one of the causes is (a loss of habitat);