Physics pls help...propagation of sound?

hi. im studying in 9th std. im from india. i have to take physics class about" propagation of sound " tomorrow. i want some simple details about that. (i have to explain that). (which is easy to understand) i want some examples and some question and answers. pls help.. thanks
Update: how does sound propagate...?
Update 2: i dont have any books about sound and i searched on wikipedia , its not that much clear.
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