Adenoids are the lymphoid tissues in which:

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

Select the correct match of disease and its symptom.

In heavy smokers,the alveoli of the lungs are enlarged and damaged,which reduces the surface area for the exchange of respiratory gases. This condition is called:

Smoking increases . . . . . . content in blood and reduces the concentration of haem-bound oxygen. Fill in the blank suitably.

What is the cause of lung cancer in coal miners?