Select the correct events that occur during
inspiration.
-(a) Contraction of diaphragm
(b) Contraction of external inter-costal muscles
(c) Pulmonary volume decreases
(d) Intra pulmonary pressure increases
(1) -(a) and (b)
(2) (c) and (d)
(3) -(a), (b) and (d)
(4) only (d)