INTRODUCTIONThe frog is one of the animals that live on land and in fresh water. Frogs are distinguished from other reptiles and fish by their specific characteristics. Generally, frogs are classified into the kingdom Animalia, the phylum Chordata, the subphylum Vertebrata, the class Amphibians, the order Anura and the family Ranidae (Amsel, 2014). The common species of frog found is Rana tigrina. The frog is actually one of the poikilothermic animals or known as cold-blooded animals. Frogs do not have a constant body temperature because their body temperature depends on the outside temperature (Prosser and Nelson, 1981). Frogs can protect themselves from predators by camouflaging themselves thanks to their small size. Frogs have streamlined bodies and legs with webbed fingers that allow them to swim. They have different skin colors depending on the species and habitat. The dorsal part of the common frog is green with the presence of black spots while the ventral part is lighter. The frog's body is made up of two parts: the trunk and the head (Bolton, 2014). In fact, the frog has no tail or neck when it turns into an adult. The head consists of two nostrils and laterally protruding eyes covered with a nictitating membrane while the trunk consists of two pairs of limbs used for locomotion. Respiration is generally the process of transporting oxygen and carbon dioxide. Typically, oxygen enters the lungs through inhalation while carbon dioxide is expelled from the lungs through exhalation (Johnson, 2012). In amphibians such as frogs, the skin and lungs are respiratory organs that participate in the breathing process. However, the circulation system involves the blood which plays a major role in transporting oxygen and nutrients to all parts of the...... middle of paper. .... eliminates most of their carbon dioxide through the skin. Under certain conditions, such as when this animal is underwater, the skin also serves as a site of oxygen absorption. Mackean (n. d) stated that when the frog is inactive, the skin can absorb an adequate amount of oxygen that it needs. On the other hand, the frog must use its throat, nostrils and mouth together to inhale or exhale the gases. because they do not have a diaphragm to help them regulate their pressure in their lungs (Miller, n. d). Cutaneous respiration is actually more important than lung ventilation in frogs in winter because their metabolisms are slow. Additionally, frogs have other respiratory surfaces than their skin which is the moist mucous membrane of the mouth. This breathing liner is used continuously when the frog's mouth is not completely submerged in water..