Find the correct statement about class Reptilia

To determine the correct statement about class Reptilia, let us analyze the characteristic features of reptiles step-by-step and compare them with the given options:

1. Skin and Scales: Reptiles are adapted for a fully terrestrial life. Their body is covered by dry and cornified skin, which prevents water loss. They possess epidermal scales or scutes (made of keratin) on their body surface. Unlike amphibians, their skin is not moist, and unlike cartilaginous fishes, they do not possess placoid scales.
2. Hearing Organs: In reptiles, there are no external ear openings. Instead, the ear is represented by a structure called the tympanum, which lies on the surface of the head.
3. Other Options Analysis:
- "moist skin and body is devoid of scales, the ear is represented by the tympanum" describes class Amphibia, not Reptilia.
- "marine habitat, endoskeleton is cartilaginous and have placoid scales" describes class Chondrichthyes (cartilaginous fishes).
- "fresh-water habitat, bony endoskeleton and air-bladder for buoyancy" describes class Osteichthyes (bony fishes).

Therefore, the statement that accurately describes the characteristics of class Reptilia is: "dry and cornified skin, epidermal scales and absence of external ears".