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 in the kingdom Animalia, phylum Chordata, subphylum Vertebrata, class Amphibia, order Anura and 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 & Nelson, 1981). Frogs can protect themselves from predators by camouflage due to their smaller size. Frogs have a slender body and have feet with webbed toes 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 black spots while the ventral part is lighter. The frog's body is composed of two parts: trunk and head (Bolton, 2014). In fact, frogs do not have tails or necks as they become adults. The head is made up of two nostrils and eyes protruding laterally covered by a nictitating membrane while the trunk is made up of two pairs of limbs which are used for locomotion. Respiration generally is the process of transporting oxygen and carbon dioxide. Generally, 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 involved in the breathing process. However, the circulation system involves blood which plays an important role in transporting oxygen and nutrients to all parts of the... middle of paper... ....eliminates most of its carbon dioxide through the skin . Under certain conditions, such as when the animal is underwater, the skin also serves as an oxygen absorption site. Mackean (n. d) established that when the frog is inactive, the skin can absorb an adequate amount of oxygen that the frog needs. On the other hand, the frog must use its throat, nostrils, and mouth together to inhale or exhale gases since they lack a diaphragm to help them regulate the pressure in the lungs (Miller, n. d). Skin respiration is actually more significant than lung ventilation in frogs during the winter as their metabolism is slow. Additionally, frogs have other breathing surfaces besides the skin which is the moist lining of the mouth. This breathing cover is used constantly when the frog's mouth is not completely submerged in water.