In COPD w hich is true -

Ans. is 'a' i.e., FEV1 / FVC < 0.7 The lung function tests in obstructive lung disease can be summarized as -o Forced expiratory vital capacity (FEVc)- Normal to slightly decreasedo Forced expiratory volume in 1 secQ (FEV )-Decrease out of proportion to FVCo FEV1/FEV1Q-Decrease can be as low as 20% - 30%o Peak expiratory flow rate-Decreasedo Total lung capacity-Increaseo Residual volume-Increaseso Functional residual capacity-Higher