Question

what are the common features between all the respiratory organs

Answer 1

They are all made up of cells and tissues.

Answer 2

Some common features are as follows:
1)All animal's respiratory organs are supplied with numerous no. of blood vessels.This help in the exchange of gases.
2)Are extensible so that right amount of air can be filled to fulfill the gaseous exchange.
3)Are usually sac-like structure.
4)Usually soft and delicate.
5)Contains villi to increase the surface area.