Answer:
Fishes have a very particular respiratory system, which manages to extract the dissolved air from the water. They do it thanks to the gills, membranes located on the sides of their body. When the animal opens and closes its mouth, the liquid enters its interior through them and that is when the blood vessels absorb the necessary oxygen. If the water has toxic components or dirt, there will not be the necessary amount of oxygen.
Explanation:
Fishes obtain the oxygen they need from the water through the gills: membranous structures supported in turn by cartilaginous or bone structures. The gill surfaces are very wide, and respiratory gases are exchanged between blood and water as it flows over them. The fish takes water through its mouth and, through a complex process, releases the water through the lids, previously passing through the lamellae, where oxygen is captured. If the water has toxic components or dirt, there won’t be the necessary amount of oxygen, there would be impurities that limit oxygen. Pollution causes the loss of oxygen. Efficient oxygen absorption from water (as gills do) is essential for active organisms in the aquatic environment. Fishes promote gas exchange by ventilating the gill surfaces, either by actively pumping water through the gills, or by continuously swimming with their mouths open. In the end, the fish die because they cannot find what they need to live.
