AIIMS 2018 Biology Reptilia MCQ Question

Option B is correct because crocodiles, as members of the Reptilia class, possess a tympanum that functions as an external ear, allowing them to detect sound effectively in their environment. Option A is incorrect since chelonians (turtles) have a three-chambered heart, not a four-chambered one. Option C is misleading because Ophiosaurus, a type of legless lizard, does not have a true external ear; instead, it has a tympanum covered by skin. Option D is incorrect as well, as Salamandra (salamanders) belong to Amphibia and have moist skin rather than dry and scaly skin typical of reptiles.