Reply #50: Those are all fit my explanations.

[HiFructosePronSyrup]

"economic disparities"

That's #1. Racial discrimination, could be fixed by affirmitive action.

"cultural differences toward taking the test, lack of preparedness"

That's #2. The belief that black people are inferior. Again, can be addressed with affirmative action.

"and on and on."

Anything that doesn't fit into the two categories I already described?

"As for grades, are you saying grading is racially biased too?"

Yes, of course they are. It's well known. Black students get lower grades for the same quality of work. They're also more harshly punished for the same disciplinary problems.