Question

What specific features make the exchange of gases in gills and lungs possible?

Answer 1

All the respiratory organs have large surface area to transport/exchange enough oxygen.
They have thin walls for easy diffusion and exchange of respiratory gases.Also, all the respiratory organs such as skin, gills and lungs, have a rich blood supply for transporting respiratory gases....

hope this will help you.

Answer 2

In lungs, there are small sacs called alveolar sac which exchange gases in lungs. These alveolar sacs are present in bunches increase the surface area , contain thin walls which makes the exchange easier.

The exchange of gases takes place in gills because of the large surface area of gills and the number of capillaries present around the gills. The exchange is more efficient because of the presence of gill filament.