Why do you think this appeal system is necessary in the legal system?

It provides accountability to the litigants.

Explanation:

An appeal is a provision in a legal system that provides an individual the right to request a higher court to review a lower court's decision in a legal suit.Through this provision, the litigant or the judge holds accountable to serve in a legal and unbiased manner.In an appeal case, the appeal lawyer may present facts and law to the higher courts that indicates an error in the decision of a lower court and thus, requests the higher court to reverse the decision of the lower court.

Race, for example, the chinese exclusion act