Question

explain the mechanism of breathing in human beings .

Answer 1

Diaphragm is made up of muscles which form the floor of chest cavity, where lungs are situated. Steps of breathing mechanism in humans:
i) Inhalation: During inhalation rib cage moves up and out and, diaphragm contracts and move down. ...
ii) Exhalation: Exactly reverse of inhalation occurs in exhalation.

Answer 2

There r 2 processes which takes place during the mechanism of breathing
 1)Inhalation- The taking in of oxygen
During Inhalation, the lungs expand, the diaphragm contracts and rib cage moves upwards and outwards.
2)Exhalation- Process by which Carbon dioxide in given out
During exhalation, the lungs and diaphragm regains its original position and the rib cage gets smaller