Explain how fish suck in water to in the intake of oxygen. include in this how the mouth and operculum work together in this process.

Most fish exchange gases using gills on either side of the pharynx (throat). Gills are tissues which consist of threadlike protein structures called filaments. These filaments have many functions including the transfer of ions and water, as well as the exchange of oxygen, carbon dioxide, acids and ammonia.Each filament contains a capillary network that provides a large surface area for exchanging oxygen and carbon dioxide. Fish exchange gases by pulling oxygen-rich water through their mouths and pumping it over their gills. In some fish, capillary blood flows in the opposite direction to the water, causing countercurrent exchange. The gills push the oxygen-poor water out through openings in the sides of the pharynx. Some fish, like sharks and lampreys, possess multiple gill openings.

Observations are things that can be directly seen and talked about. Inferences are things that you believe correlate with each other. For instance, the dog wagging its tail must be happy because it is a guess, not a fact. An example of an observation is The girl is wearing a blue shirt with white straps because you can directly see it.