The characteristics of Class Reptilia are (a) body covered with moist skin which is devoid of scales, the ear is represented by a tympanum, alimentary canal, urinary and reproductive tracts open into a common cloaca (b) fresh water animals with bony endoskeleton, airbladder to regulate buoyancy (c) marine animals with cartilaginous endos keleton, body covered with placoid scales (d) body covered with dry and cornified skin, scales over the body are epidermal, they do not have external ears.
Option D Reptiles represent the first class of vertebrates fully adapted for life in dry places on land. The characters of reptiles are in fact a combination of characters that are found in fish and amphibians on one hand and birds and mammals on the other. Their exoskeleton is of horny epidermal scales, shields, plates and scutes. The skin is dry, cornified and devoid of glands. Reptiles lack external ears and have immovable eyelids.
