Practice question

Respiration in adult frogs employs trimodal surfaces across seasons: cutaneous diffusion through highly vascularized thin moist skin effective both in water during hibernation under mud and on land, pulmonary respiration via paired sac-like septate lungs ventilated by positive-pressure buccal pumping expanding lungs, and buccopharyngeal respiration through highly vascular lining of oral cavity showing rhythmic throat oscillations enabling air sampling. Combined utilization allows tolerance to diving, overwintering anoxia and vocalization. Not restricted to single mode unlike mammals dependent solely on lungs for gas exchange.