'Q' will be the first part of the given sequence as 'man lived entirely by hunting' (about ten thousand years ago) is one of the 'ways of life' mentioned in the opening part of the given sequence. 'R' will come next as it states that 'settled civilisation' began when agriculture was discovered. 'S' will follow next because it says that after the development of agriculture, civilisation has always been changing. 'P' will come next as it states the continuous progress of changes that took place as a result the history never stood still. Hence, QRSP is the correct sequence. Thus, option (a) is correct.