Yahoo and Google SERPS

Does Yahoo uses the Search Results of Google??

This is no more true.

Previousy Yahoo Search Engine use to show the search results from Google but now this is no more true. Now Yahoo owns Overture and uses its database to show results in its search pages  (SERPS).

Unlike as previous now getting a top rank on Google doesn't means that you will get the same rankings on Yahoo also. Now both search engines follow the different algorithims to rank the sites in their Search Engine Results Pages (SERPS).