Final answer:
Giant molecular clouds of gas in the Milky Way are found in the spiral arms of the galaxy, which contain dense interstellar material and sites of new star formation.
Step-by-step explanation:
In our galaxy, the Milky Way, giant molecular clouds of gas are primarily found in the spiral arms. These spiral arms are regions characterized by relatively dense interstellar material and young stars. The arms emerge from the central bar of the galaxy and contain bright emission nebulae, hot young stars, and are regions where new star formation is still occurring. In contrast, the halo of the galaxy contains older stars and most of the globular clusters, while the galactic center is known for harboring a supermassive black hole. The gaseous distribution within the galaxy indicates that there are two major spiral arms and several fainter arms and short spurs, indicating that spiral arms are a defining feature of the Milky Way's disk structure.