... formations should not be confused with stellar clusters, globular clusters of stars that exist within a galaxy. The size of galactic clusters varies enormously, with some clusters containing only ... largest galaxy in the group; the Milky Way, the second-largest galaxy; and the Trianglum Spiral, the third largest. There are also four medium-sized spiral galaxies, includ- 10 ing the Large Cloud ... amounts of “dark matter”, which cannot be directly observed but which generates gravitational pull. This matter includes gas, dust, burnt-out stars, and even black holes. 46. Which of the followings...