Answer:
With its natural borders - the Sahara Desert to the west, the mountainous Eastern Desert and the Red Sea to the east, the Mediterranean Sea edging the marshy Delta to the north,and the Cataracts to the south, ancient Egyptians were reasonably free from invaders. The Nile River flows from south to north through eastern Africa. It begins in the rivers that flow into Lake Victoria (located in modern-day Uganda, Tanzania, and Kenya), and empties into the Mediterranean Sea more than 6,600 kilometers (4,100 miles) to the north, making it one of the longest river in the world. The Nile River was critical to the development of ancient Egypt. In addition to Egypt, the Nile runs through or along the border of 10 other African countries, namely, Burundi, Tanzania, Rwanda, the Democratic Republic of the Congo, Kenya, Uganda, Sudan, Ethiopia, and South Sudan. Its three main tributaries are the White Nile, the Blue Nile, and the Atbara.
Explanation: