Final answer:
The term for the large spaces between superclusters with very little matter is 'cosmic voids'. Dark matter and dark energy are distinct from cosmic voids and refer to invisible matter and a force accelerating the universe's expansion, respectively. Option 3 is the correct answer.
Step-by-step explanation:
The term used to describe the huge volumes of space between superclusters that seem to contain very little matter is called cosmic voids. Cosmic voids are vast spaces that may span hundreds of millions of light-years where very few galaxies exist, as most galaxies are confined to less than 10% of the total volume of space.
These voids were not expected before their discovery; astronomers initially thought that the regions between clusters would house many small galaxy groups or isolated galaxies. However, careful searches within these voids have revealed very few such galaxies, supporting the observation that the universe at large scale is homogeneous and isotropic, conforming to the cosmological principle.
While dark matter and dark energy are also major areas of study in understanding the universe, they refer to different phenomena. Dark matter is a form of matter that does not emit or interact with electromagnetic radiation like light, making it invisible and detectable only through its gravitational effects.
Dark energy, on the other hand, is a mysterious force that is causing the expansion of the universe to accelerate. Neither of these should be confused with cosmic voids or with black holes, which are intense gravitational fields from which not even light can escape.