Question

Choose the odd one out in each of the following groups of four items each:
Trachea, Bronchus, Alveolus, Diaphragm

Answer 1

Trachea, Bronchus and the alveoli are a part of the respiratory tract.

The diaphragm is not a part of the respiratory tract and helps in the external exchange of gases. So, the odd one out is 'Diaphragm'.