Verified answer

Cluster and super clusters of galaxies.

See this article :

http://en.wikipedia.org/wiki/Galaxy_groups_and_clu...

Galaxies are arranged in gravitationally-bound clusters. These clusters are distributed throughout the entire volume of the universe is a weblike structure.

I'm afraid there's no easy answer to this one. There are numerous theories involving the shape of the universe so you're going to have to read the particular source material provided to find out which of many possible answers is wanted.