Read the following passage:

The Nile River is a major river in Africa, running for a distance of approximately 6,695 kilometers from its ___(X)___ in Burundi to its mouth in Egypt. It is the longest river in Africa and the primary source of water for Egypt and Sudan. The Nile has played a vital role in the history and ___(Y)___ of ancient civilizations in Egypt, as it provided a ___(Z)___ source of water for irrigation and transportation. The Nile is also home to a diverse array of plant and animal life, including crocodiles, hippopotamuses, and over 1,000 species of birds.