Question

what makes gills a good respiratory surface ?

Answer 1

Most living things need oxygen to release energy from food byrespiration. ... Oxygen can pass into them through this surface by diffusion. A large surface area is needed for effective gas exchange - so larger, more complex, organisms have special organs such as gills and lungs.

Answer 2

Fish carry out gas exchange using their gills. These only work when water is forced across the gill filaments, so fish are restricted to living in water.