According To definition of Lichens: Lichens are symbiotic associations of a fungus with the photosynthetic partner called as phycobiont such as green algae or cyanobacteria.gain, The two organisms live in close association with each other and both get benefit from this kind of association, this is called Symbiotic Association. By the way, Parasitic relation means living in or on another organism (host) and causing harm to it.
The White Nile (Arabic: Ø§ÙÙÙÙ Ø§ÙØ£Ø¨ÙØ¶ââ an-nÄ«l al-'abyaá¸) is a river in Africa, one of the two main tributaries of the Nile; the other is the Blue Nile. In the strict meaning, White Nile refers to the river formed at Lake Victoria, at the confluence of the Bahr al Jabal and Bahr el Ghazal Rivers.
Shorter than the White Nile, the Blue Nile starts in the highlands of Ethiopia and Eritrea, picking up black sediment en route to Khartoum. The Blue Nile is fed by monsoon rains, and when rains are abundant, the Blue Nile can actually flow backward near its confluence with the White Nile.