Final answer:
Galaxies initially formed from collapsing clouds of gas and dark matter, where dust grains condensed and gas rapidly collapsed due to gravity to create dense cores that formed stars and globular clusters, eventually leading to the creation of a galaxy's disk.
Step-by-step explanation:
The statement that best describes the formation of galaxies is D. Dust and gases contract. Initially, galaxies formed from large clouds of gas and dark matter. Parts of this gas became dense and cool, allowing dust grains to condense and form. As the gravitational force of the infalling gas increased, it overwhelmed the pressure from cold materials, leading to a rapid collapse. This process eventually led to the formation of dense cores and the creation of stars and globular clusters. The gas then settled into a rotating disk as it continued to collapse due to gravity, forming the disk of the galaxy, and further star formation took place within this structure.