Give a few features of class Amphibia.

Explanation

The general characters of class amphibia are as follows:
(i)The body is divisible into head and trünk. Neck and tail may be present or absent.
(ii) They possess two pairs of jointed pentadactyl limbs. Their digits often bear webs.
(iii) The skin is smooth and moist. The skin is rich in multicellular mucous or poison glands.
(iv) Endoskeleton is bony or cartilaginous. Notochord is absent.
(v) Alimentary canal ends in cloaca. Amphibians are the first vertebrates to have a true tongue.
(vi) Respiration occurs with the help of gills, lungs, buccopharyngal cavity and skin.
(vii) The heart is three chambered, i.e., two auricles and one ventricle.
(viii) Excretory organs are kidneys. Nitrogenous wastes are urez in adults and ammonia in larval stage.
(ix) Sexes are separate. Fertilization may be external or internal. Examples: Rana tigerina-the common Indian frog, Bufo-the common toad, Alytes-the midwife
toad, Hyla-the tree frog, Xenopus-the African toad etc.