$A$ chronic disorder in which alveolar walls are damaged due to excessive cigarette smoking is

In pneumonia, where does the fluid accumulate?

Assertion $(A):$ $A$ person goes to high altitude and experiences 'altitude sickness' with symptoms like breathing difficulty and heart palpitations.
Reason $(R):$ Due to low atmospheric pressure at high altitude,the body does not get sufficient oxygen.
In the light of the above statements,choose the correct answer from the options given below.

What is the cause of asthma?

In $emphysema$,what happens to the lungs?

$A$: Asthmatic patients use bronchodilator drugs as well as inhalers for symptomatic relief.
$R$: Asthma is characterized by the spasm of smooth muscles in the wall of bronchioles due to allergens.