There is a theory that gravity could pull galaxies back together, causing a reverse big bang.

which observation makes this theory less likely than the idea that the universe may continue to expand

The options

A. Background radiation is present.

B. Galaxies exist outside of the Milky Way.

C. The expansion of the universe is accelerating.

D. Gas giants form farther from the Sun, where temperatures are cooler.

The CORRECT ANSWER IS C.

C. The expansion of the universe is accelerating.

Explanation:

It's important to note that latest observations of the universe have revealed that the universe is enlarging at a high level of speed. It connotes that the universe is still developing and it can be observed that all the stars, planets and galaxies are quite in distant from one and other. We can say it in a layman way, from the movie Harry Potter, Harry Potter and the inmate of Azkaban, Harry's aunt inflates just the way a balloon will inflates, which causes her clothes to tear with time and stretch also. The Universe can be seen to be at a development stage like Harry's aunt, with the galaxies being observed to be moving, such as its distancing from one and other, just as the buttons of Harry's aunt dress. Therefore, the correct answer is: The expansion of the universe is accelerating

well, i believe that the answer is 2. : 3