Ancient Egypt

I need support with this History question so I can learn better.

1)Why is ancient Egypt controversial for historians?

2)What was the most notable achievement of the Old Kingdom? How might have this resulted in their downfall?

3)How did the Middle Kingdom attempt to compensate for the mistakes of the Old Kingdom? What NEW mistakes did their leaders make?

4)Likewise, how did the New Kingdom differ from the previous periods of Egyptian history?

5)What significant role did Egypt fill even after it was conquered by other states (Persia, Greece, Rome, Muslim caliphates)?