The existence of stellar-mass black holes across the galaxy requires what condition regarding the star's pre-collapse life?

Answer

That stars must have lost a massive, yet specific, amount of material before core collapse.

The observation of black holes confirms that progenitor stars were efficient at losing mass throughout their evolution, as retaining too much initial mass would otherwise have resulted in a neutron star remnant instead.

The existence of stellar-mass black holes across the galaxy requires what condition regarding the star's pre-collapse life?
starradiationmassevidencestellar wind