What challenges did the Little Rock Nine face in Central High after the initial opening?

Physical and verbal attacks.

Explanation:

Challenges such as physical attacks as well as verbal attacks were faced by the Little Rock Nine in Central High after the initial opening. These physical and verbal attacks done to these nine students by white students throughout their studies at the Central High. Minnijean Brown fought back against these attacks but was expelled from the school while the remaining eight students attended the school for the rest of the academic year and bear these physical and verbal attacks.

a direct vote in which an entire electorate is invited to vote on a particular proposal. this may result in the adoption of a new law.  

i would say it is the roman empire europe after the norman conquest.