How do scientists define an astronomical unit ?

a unit of measurement equal to 149.6 million kilometers, the mean distance from the center of the earth to the center of the sun.

Explanation:

the answer is because he is black and completly stupid.

answer: i looked it up

explanation: in 1955 in montgomery, alabama, a girl refused to give up her seat on a public bus. the girl was black, and the passenger looking to take her seat was white. this is a familiar tale, but it's not about rosa parks. the girl in the story is a 15-year-old high school student named claudette colvin, and this act of defiance occurred nine months before rosa parks did the same thing. colvin was arrested, and her case is what led to the u.s. supreme court's order for the desegregation of alabama's bus system. so, why don't we know colvin's name? "later i had a child born out of wedlock; i became pregnant when i was 16," colvin says. "and i didn't fit the image either, of, you know, someone they would want to show off.