Page 1 :
Frogs are belong to class Amphibia of phylum Chordata. The most common species of frog found in India is Rana tigrina. Their body temperature varies with the temperature of the environment. Such animals are called cold blooded or poikilotherms They have the ability to change the colour to hide them from their enemies (camouflage)., The skin is maintained in a moist condition. The frog never drinks water but absorb it through the skin. Body of a frog is divisible into head and trunk. A neck and tail are absent. Above the mouth, a pair of nostrils is present., On either side of eyes a membranous tympanum (ear) receives sound signals. Feet have webbed digits that help in swimming. Frogs exhibit sexual dimorphism. Male frogs can be distinguished by the presence of sound producing vocal sacs and also a copulatory pad on the first digit of the fore limbs which are absent in female frogs., DIGESTIVE SYSTEM, The digestive system consists of alimentary canal and digestive glands. The alimentary canal is short because frogs are carnivores and hence the length of intestine is reduced., The mouth opens into the buccal cavity that leads to the oesophagus through pharynx. Oesophagus is a short tube that opens into the stomach which in turn continues as the intestine,rectum and finally opens outside by the cloaca. Liver secretes bile that is stored in the gall bladder. Pancreas, a digestive gland produces pancreatic juice containing digestive enzymes.