The Nile River

    The Nile River is the longest river in the world. Its length is around 4.180 miles. It flows through Uganda, Sudan and Egypt. It has two main tributaries. They are the Blue Nile and the White Nile. The White Nile stars in the Great Lakes region of central Africa. The Blue Nile begins at Lake T’ana in Ethiopia. These two rivers meet near Khartoum the capital city of Sudan.
    There is another shorter tributary. It’s Atbaram river, or also known as the Black Nile. However, this river flows only while there is rain in Ethiopia and dries very fast. The Nile River ends in Mediterranean Sea.         
  The Nile River is important for agriculture, food, transportation and tourism. Farmers grow wheat, sorghum, citrus fruit, sugarcane and cotton along the Nile River, and they use the river to water their crops and plantation. People also fish this river. The river is used to transport goods to different places along its long path. The ships can travel up using the sail, and down using the flow of the river.
     Tourism is another main advantage of The Nile River. Some special places to visit are Aswan, Luxor, Giza, Cairo and Khartoum. People who like adventure will find traveling this river exciting.

"It has two main tributaries"
The word it refers to ...