Rationale: Insect wings are composed of layers of cuticle, which can be modified to be leathery (somewhat flexible and tough), horny (hard and rigid), or membranous (thin and flexible), depending on the insect species and the wing's function. This variation in texture is a key characteristic of insect wings. Why the other options are incorrect: - a. Mouth: Insect mouthparts are highly variable in structure and function, adapted to their specific diets. While some components might be hardened (li