What role does a supernova play in the life cycle of a star?

A supernova marks the end of a star's life cycle, specifically for massive stars that have exhausted their nuclear fuel. When a massive star runs out of the elements needed for fusion, it can no longer support itself against gravitational collapse. This leads to the core collapsing to an extremely dense state, and ultimately, a violent explosion occurs, ejecting the star's outer layers into space. This explosive event not only signifies the death of the star but also plays a crucial role in enriching the surrounding interstellar medium with heavy elements, which can eventually contribute to the formation of new stars and planets. The energy and material ejected during the supernova can trigger the formation of new stars, thus continuing the cycle of stellar evolution.

The other options do not accurately describe the role of a supernova. While a supernova can lead to the creation of neutron stars or black holes depending on the original mass of the star, it does not rejuvenate the star or simply make it shine brighter before its death. Instead, it represents a dramatic conclusion to the star’s life, paving the way for future generations of stars.