How would the universe be different if massive stars did not explode at the wnd of their lives

The extreme energy released in supernovae actually destroys the nuclei of atoms, causing heavier elements to reform and dispersing them throughout the universe. Before supernovae, the only three elements in the universe were hydrogen, helium, and lithium. More stable elements like carbon and oxygen that are necessary for life were created by them, and without them, we could not exist.