Because they were banned for life after one was killed
He was an author so he contributed by writing books to acknowledge the age of enlightment of literature and... other things!
2 African Americans have served in the Supreme Court
This process is natural selection<span>. The traits that confer an advantage to those individuals who leave more offspring are called </span>adaptations<span>. In order for </span>natural selection<span> to operate on a trait, the trait must possess heritable variation and must confer an advantage in the competition for resources.</span>