Dry, horny scales in reptiles help them to

Step 1: Analyze the question The question asks about the function of dry, horny scales on a reptile's body.

Step 2: Explain the concept Reptiles (lizards, snakes, crocodiles, tortoises) are adapted to life on land. Their skin is covered with keratinized (horny) scales. Keratin is a tough, waterproof protein, also found in your fingernails and in the hair of mammals. This covering is a key terrestrial adaptation, because land animals are always at risk of drying out (desiccation).

Step 3: Evaluate the options

• A. Carry out gaseous exchange: Wrong. Reptiles breathe with lungs. The dry, scaly skin is not used for gas exchange. That is true of amphibians, which have moist, thin skin.
• B. Escape from predator: Wrong. The scales offer some protection, but that is not their main function.
• C. Facilitate movement: Wrong. Movement is achieved by limbs or by muscular body movement in snakes. The scales are not the main factor.
• D. Look for mating partners: Wrong. Mate-finding relies on senses such as smell and sight, not on the scales.
• E. Prevent water loss: Correct. The dry, horny, waterproof scales reduce evaporation from the body surface, so reptiles can live in dry habitats.

Step 4: Answer The correct option is **E, prevent water loss.

Exam tip: Link features to habitat. Amphibians have moist skin, so they stay near water and use their skin for gas exchange. Reptiles have dry, scaly skin that prevents water loss, so they are fully adapted to land. Other reptile adaptations include internal fertilization and shelled eggs, which also help prevent drying out.