When justice lewis powell stated that racial and ethnic distinctions require the most “exacting judicial examination,” he meant these qualities required

Justice Lewis Powell meant that racial and ethnic distinctions require "extremely precise consideration". Powell had many liberal ideas, including that noone could be discriminated for its race or ethinic background. For example, he stated that at a university admission process, a school could not set aside openings for any specific demographic.  

asthenosphere/ lithosphere would be the answer