Workbook Integrated Exercise (P.39)

4.        (a)    (i)     B to C, D to E

                (ii)    N to P, R to T

        (b)    The chest volume decreases while the gas pressure inside the chest increases.

        (c)    (i)     The intercostal muscles relax, causing the ribs move downwards and inwards. Hence, the volume inside the chest decreases.

                (ii)    The diagram moves upwards, thus the volume inside the chest decreases.