What are strong rapids in a river called?

What was the reed called that grew on the banks of the Nile, which the ancient Egyptians used in a variety of ways?

What is the triangle shaped area of marshy land made by soil deposited by a river called?

Which of the following would make travel dangerous along the Nile River?

What could you use to create string for a necklace?

Which of the following was only located at the mouth of the Nile River?