how can a frog respire through it's skin...??
Frog - as an amphibian, during its tadpole stage, breathes through its gills and skin. When turn into an adult frog, it grows lungs and looses gills and continue to breathe through its skin with tiny blood vessels, capillaries under the outer skin layer. It is called cutaneous gas exchange.
During hibernation, frogs don’t need as much oxygen. They only breathe through their skin at these times. They get oxygen in water or air through a thin layer of moisture. When the frog is hopping around on land, it cannot get enough oxygen through its skin only. Then it breathes through its nostrils also.