What are the three levels into which most federal and state cases are divided?

Most federal and state cases are divided into three levels as a result of the courts that handles them, the courts are district courts, courts of appeals and supreme courts. 
The district courts are the lowest on the rung and were created hear lower cases. The courts of appeals are the one that hear all federal appeals while the supreme court, which is the highest on the rung is consider as the final court of appeal.

Answer: the dna polymerase checks for errors in dna to prevent replication mistakes.
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