Q.Mention two modifications in reptiles required for terrestrial mode of life.

Two modifications that suit reptiles to a terrestrial life:

• Dry, cornified skin bearing epidermal scales or scutes, which resists water loss on land — unlike the moist skin of amphibians that must stay wet. …

Moving fully onto land, away from the dual aquatic-terrestrial life of amphibians, required reptiles to solve two basic problems: preventing water loss through the skin, and reproducing without needing standing water.

• Dry, cornified skin with scales or scutes: reptilian skin is dry and cornified, bearing epidermal scales or scutes. This tough, non-moist covering greatly reduces water loss compared with the moist, glandular skin of amphibians, which must stay wet to function (including for respiration). …

Method: Contrast-with-amphibian derivation

Instead of listing reptilian adaptations directly, start from the SPECIFIC limitations amphibians face on land (since reptiles evolved from amphibian-like ancestors to overcome exactly these limitations), and derive each reptilian modification as the fix for one named amphibian weakness.

Amphibian weakness 1 — water loss through the skin. Amphibian skin is moist and must stay wet, partly because it doubles as a respiratory surface; this makes amphibians highly vulnerable to drying out and largely confines them to damp habitats or requires them to return to water periodically.

Reptilian fix 1: skin that is dry and cornified, bearing epidermal scales or scutes. This tough, non-permeable covering resists water loss far more effectively than moist amphibian skin, freeing reptiles from the need to stay near damp conditions.

Amphibian weakness 2 — reproduction tied to water. Most amphibians rely on external fertilization, meaning sperm must reach the egg through a surrounding watery medium — which ties amphibian reproduction to ponds, streams or at least a wet surface, even for otherwise fairly terrestrial adult amphibians. …