What two forces balance each other to keep a nebula from collapsing?

In a nebula, gravitational forces act to pull the gas and dust inward, while thermal pressure, generated by the heat from the particles and radiation from nearby stars, acts outward to counterbalance this gravitational pull. The balance between these two forces prevents the nebula from collapsing under its own gravity, allowing it to maintain its structure until conditions change, potentially leading to star formation.