Answer to Question 1
The skin of reptiles has a horny surface layer. In lizards and snakes, this horny layer forms a hard, continuous
covering of scales. As the animal grows, this outer layer is shed, allowing for further growth.
Crocodiles, alligators, and some lizards have bony dermal scales covered by a horny epidermal layer,
which must be shed to allow for body growth.
Answer to Question 2
Crocodiles, alligators, caimans, and gharials have long bodies and long, clearly defined tails. Their limbs are
usually paired and attached to their bodies at right angles. This enables the animal to lift its body up off the
ground when moving. The limbs of crocodiles and alligators are strong and powerful.
Crocodiles and alligators have bony, dermal scales covered by a horny epidermal layer, which must shed to
allow for body growth. They have three-chambered hearts.
Photograph of the skin eruptions associated with shingles.
Color enhanced X ray of large malignant tumor in the right lung.
Color-enhanced scanning electron micrograph of HIV virus (red) infecting T-helper cells (green).
Anatomy of the skin. Illustration of a section of skin showing key structures.
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