Which of the following is not a part of the respiratory system ?

1. Nostrils
2. Lungs
3. Mouth
4. Trachea

The basic structural and functional unit of the lungs is :

1. Pleura
2. Alveolus
3. Capillary
4. Diaphragm

Correct the following statements by changing the first/ last word only :

1. BCG is a kind of vaccine used to prevent Pneumonia.
2. Streptomycin is a kind of vaccine.
3. Breathing is a bio-chemical process.
4. The amount of oxygen in expired air is 21%.
5. The front opening of the trachea is guarded by a muscular flap called diaphragm.

Define the terms given below :

1. Respiration
2. Breathing
3. Lungs
4. Inhalation
5. Exhalation