Well im not to sure who took the pic but i think it was taken to captrue the queser/waterfall wut ever it is, and its purpose was to show the ppl wut some might think is a beautiful sighting.
sorry if this is wrong :)
C) The composer may wish to use certain instruments to support other instruments; as the bass and harmony support the melody.
Its true cause it wont be a square without 2 sets of couples