What is a characteristic feature of molecular clouds in the Milky Way?

Molecular clouds, also known as stellar nurseries, are indeed the primary sites of star formation within the Milky Way. These clouds are composed mostly of hydrogen molecules, along with dust and other gas compounds, creating an environment conducive to the process of star formation. In these dense regions, the temperature and pressure conditions facilitate the gravitational collapse of material, ultimately leading to the birth of new stars.

The composition of molecular clouds is predominantly lighter elements such as hydrogen, making them less rich in heavy elements compared to certain other regions of the galaxy. Although some molecular clouds may eventually deplete their gas as stars form and evolve, it is their role as locations where new stars are actively born that defines their significance in the galactic landscape.