I'm sure it's the Tropical forest.
Hope this helps!
A primary source provides direct or firsthand evidence about an event, object, person, or work of art. Primary sources include historical and legal documents, eyewitness accounts, results of experiments, statistical data, pieces of creative writing, audio and video recordings, speeches, and art objects.
The Berlin wall was a barrier that existed from 1961 to 1989 throughout conflict and separated East and city district. It symbolized the distinction between western democrats and jap communists (end of soviet domination) and therefore the method they thought FRG ought to be lead. Fall of Berlin wall could be a major event in European history. The policies of restructuring and openness initiated by soviet leader Mikhail opened the trail for the destruction of the symbolic physical barrier.
