Final answer:
Stars form from interstellar clouds through a process of gravitational collapse and protostar formation.
Step-by-step explanation:
Stars form from interstellar clouds, which are large clouds of gas and dust in space. These clouds are primarily composed of hydrogen and helium, along with trace amounts of other elements. As these clouds become denser and more gravitationally unstable, they begin to collapse under their own gravity.
The collapsing clouds then undergo a process called protostar formation, where the gas and dust in the cloud condense and heat up. As the protostar continues to accrete more mass, it eventually reaches a point where the pressure and temperature at its core become high enough for nuclear fusion to occur. At this point, the protostar becomes a main sequence star and begins to generate its own energy through nuclear reactions.
So, stars form from interstellar clouds through a process of gravitational collapse and protostar formation.