Question

which is the final event that occurs when a star is forming? the outer layer of the star expands gravity pulls gas and dust together a black hole forms as the core collapses nuclear fusion begins under high pressure

Explanation:

The process of star - formation starts with gravity pulling gas and dust together. As the mass accumulates and the pressure and temperature in the core increase, nuclear fusion begins under high pressure. This is the final key event in the formation of a star. A black hole forms in the later stages of a massive star's life, not during star - formation. The outer layer expanding is also a later stage phenomenon for some stars.

Answer:

Nuclear fusion begins under high pressure