According to context clues, which is the best definition of event horizon?

One central theme of phillis wheatley's "on being brought from africa to america" is that

What best describes the transportation within cities in the early 1800s

Plyler v. doe did the following except: established that u.s. citizen children whose parents have been deported may petition to bring the parents back into the country. established that children regardless of immigration status may not be denied a public school education. resulted in the texas law being struck down because it was a state law rather than a federal law. gave children a form of heightened scrutiny even though it has not changed the constitutional review of most classifications.