Question

why are gills in fish supplied with blood capillaries​

Answer 1

Answer:

Oxygen and carbon dioxide dissolve in water, and most fishes exchange dissolved oxygen and carbon dioxide in water by means of the gills. ... The blood capillaries in the gill filaments are close to the gill surface to take up oxygen from the water and to give up excess carbon dioxide to the water

Answer 2

Fish are a class of aquatic vertebrates. The combination of gills, fins and the fact that they live only in the water make fish different from all other animals. And some...not so much. Fish spend all of their lives in the water and are cold-blooded with the exception of Tuna family and the Mackerel shark family.