Question

During exhalation, the ribs
(i) move outwards (ii) move downwards
(iii) move upwards(iv) do not move at all
Topic: Respiration in Organisms

Answer 1

(ii) move downwards.....due to decrease of the volume of thoracic cavity of lungs....

Answer 2

During exhalation, the ribs move downwards.

The correct option is (ii).

Our diaphragm contracts and moves downward when we breathe in. It is because of this that the space in our chest cavity increases into which the lungs expand.  The intercostal muscles between our ribs also support expand the chest cavity.