Question

on the largest scales, the universe is made of voids and filaments. these filaments are made of: chains of isolated stars chains of clusters of galaxies chains of black holes chains of white dwarfs

Explanation:

On the largest cosmic scales, the universe's structure consists of filaments (dense regions) and voids (empty regions). Filaments are composed of chains of galaxy clusters, as galaxies and their clusters are the large-scale building blocks of the universe, not isolated stars, black holes, or white dwarfs which are smaller celestial objects.

Answer:

chains of clusters of galaxies