Q4. Assertion: emphysema reduces gas exchange. Reason: in emphysema the alveolar walls are damaged, so the respiratory surface decreases. Are both true, and does the reason explain the assertion?
Both are true, and the reason explains the assertion (NCERT page 190).
Q5. In which kinds of industries does NCERT say occupational respiratory disorders are common, and why?
Industries involving grinding or stone-breaking, where so much dust is produced that the body’s defence mechanism cannot fully cope (NCERT page 191).
Q6. What sound does asthma typically cause, and why?
Wheezing, because the bronchi and bronchioles are inflamed and breathing is difficult (NCERT page 190).