In option 1, the flying fish, respiration is not done by the skin. Flying fish are able to extract oxygen from the air using specialized organs called gills, which are located in their gill covers. This allows them to breathe underwater.
In option 2, the sea horse, respiration is also not done by the skin. Sea horses have gills, similar to other fish, which they use to breathe underwater. They do not have lungs like mammals to breathe air.
In option 4, the chameleon, respiration is not primarily done by the skin. Chameleons have lungs, like other reptiles, which they use for respiration. They do not have the ability to extract oxygen directly from their skin.
Therefore, the correct option is option 3, the frog. Frogs are unique among these options because they have a special adaptation that allows them to respire through their skin. This process is called cutaneous respiration. Frogs have thin and permeable skin that allows oxygen to diffuse directly into their bloodstream. While they also have lungs and can breathe using them, their skin provides an additional surface area for gas exchange. This is particularly important for frogs living in aquatic environments, where they can absorb oxygen directly from the water