Posted by qwerty on .
Most of the energy in the Universe today is...
- contained in the motion of galaxies.
- released through supernova explosions.
- in the form of dark energy.
- the energy of the CMB photons.
Your teacher probably wnats you to say "dark energy". However, this is a hypothetical energy-matter. There are a number of smart folks who are doubting this hypothesis, and as it stands now, there is little observational evidence that confirms this hypothesis.