In this disease,the respiratory surface area decreases.

Select the correct option:
$(1)$ Nasal cavity acts as an air conditioner.
$(2)$ Cigarette smoke causes emphysema.

When $O_2$ is inadequate during respiration,the condition is called:

What are the symptoms of $Altitude$ $Sickness$?

$A$: Emphysema is a chronic obstructive pulmonary disease,causing irreversible distension and loss of elasticity of the alveoli.
$R$: Emphysema is preventable if chronic exposure to smoke (cigarette and others) and pollutants is avoided.

Which of the following is a characteristic of asthma?