Why was the origin of life a sample step in the Earth's history?

Why was the origin of life a sample step in the Earth's history? Why the water is the origin of life on earth? 麻烦帮忙分析一下这个句子的结构～Why was the origin of life a sample step in the Earth's history? What was the origin of Man?人类的起源是什么?我把他改成what was man's origin Why was the river rich? Why was O.J.Simpson murder case called Trial of the Century?What kind of judicial phylosophy did it reflect? The origin of go and the place if it's development was in ancient China. the origin of language （ Why was the American civil war? why was the teacher very angry? Why KoKo was slow in the race? Why was the writer is aunt surprised? Why was Pat fast in the race? Why was the writer is aunt surprised? 求翻译The package was returned to its origin.I can forward to: The reason why he was late was true . the origin of the dressroom Who can tell me history of English?Please talk about English of Origin,who was first invented it by?Why English became very popular language now?(in English)