which of the following diagrams best represents the size relationships among galaxies, stars, and the…

Brief Explanations:

The universe is the largest entity that contains galaxies. Galaxies, in turn, contain stars. So the correct hierarchical order from largest to smallest is Universe > Galaxies > Stars.

Answer:

The diagram with the Universe as the outermost layer, Galaxies in the middle layer, and Stars as the innermost layer is the correct one.