Is endosymbiosis a valid scientific theory? how?

The endosymbiotic theory is the accepted mechanism for how eukaryotic cells evolved from prokaryotic cells. First published by Lynn Margulis in the late 1960s, the Endosymbiont. Theory proposed that the main organelles of the eukaryotic cell were actually primitive prokaryotic cells that had been engulfed by a different, bigger prokaryotic cell.

regents of the university of california v. bakke, 438 u.s. 265 (1978), was a landmark decision by the supreme court of the united states. it upheld affirmative action, allowing race to be one of several factors in college admission policy.