Statement should start the paragraph as it opens the idea by talking about the development of songs in birds. Statement 4 and 5 form a pair because statement 4 speaks of a prescribed path, and statement 5 describes that path (beginning, passing and achieving). So the odd sentence has to be either 3 or 2 . Statement 2 is more likely to be a part of the paragraph because it talks about the bird species having a single song or a range of songs. The right sequence could be 1245.3 does not fit into the sequence, and is the odd one out.