Bucket-handle movement is seen in

Lungs do not collapse between breaths and some air always remains in the lungs which can never be expelled because

Which of the following activities does not take place during pulmonary respiration in amphibians (e.g.,frogs)?

Explain the process of inspiration under normal conditions.

Arrange the given steps by which the lungs show inspiration,in the sequence of events occurring first:
$I.$ Increase in the volume of the thoracic chamber in the dorsoventral axis
$II.$ Upward and outward movement of the ribs
$III.$ Contraction of intercostal muscles
$IV.$ Entry of air inside the lungs
$V.$ Contraction of the diaphragm
$VI.$ Increase in the volume of the thoracic chamber in the anteroposterior axis
Choose the correct option.

State whether the given statements are true or false.
$I.$ Ventilation in humans is an active process.
$II.$ Diaphragm helps in generating the pressure gradient in the lungs.
Choose the correct option.