K.C.S.E Biology Q & A - MODEL 2014PP1QN12
The diagram below represents a model used to demonstrate breathing in mammals.
(a) Name the mammalian structure represented by the parts labelled D and E.
(i) D .
(b) State the observation made when the string is pulled downwards.
(c) Explain the observation in (b) above.
(a) (i) Rib-cage/chest cavity;
(b) The balloons are inflated;
(c) Pulling down the string increases the volume of D, hence decreasing the pressure inside:
The low pressure causes external atmospheric air to rush in and inflate the balloons;