Answer:
Fish have gills in order to extract oxygen from the water and absorb it into their bloodstream. This allows them to breathe underwater, as opposed to mammals like humans who require air to breathe. states that "gills require a huge amount of water to provide the necessary gas exchange. The gills also pass carbon dioxide into the water in the same way as lungs breathe it out into the air. As the water passes over the gills, the blood in the fish absorbs oxygen from the water."
Option 2, "to absorb oxygen from the water into the bloodstream," is the correct answer. Gills do not absorb nutrients from the water into the digestive system (option 1), transport oxygen to the lungs (option 3), or regulate body temperature (option 4). also mention that gills are used by fish to expel nitrogenous waste and regulate the pH or acidity in their bodies, but the primary function of gills is to extract oxygen from the water and absorb it into the bloodstream.
Step-by-step explanation: