<Ul> <Li> Apito or samba whistle </Li> <Li> Siren </Li> <Li> Slide whistle </Li> <Li> Whistle or police whistle </Li> </Ul> <Li> Apito or samba whistle </Li> <Li> Whistle or police whistle </Li> <P> When classifying instruments by function it is useful to note if a percussion instrument makes a definite pitch or indefinite pitch . </P>

Which one of these percussion instruments is not