What best defines a structural adaptation in organisms?

• A. A genetic mutation with no effect
• B. A physical feature of an organism's body that contributes to survival
• C. A temporary change during a storm
• D. A behavior learned from other organisms

Answer: (B)

Structural adaptation is a physical part of an organism’s body that helps it survive in its environment. This trait is usually inherited and stays with the organism across generations. Examples include a turtle’s protective shell, a bird’s beak shaped for its food, or a cactus with spines that reduce water loss and deter predators. These features are about the body itself, not something the organism does or learns. That’s why a genetic mutation with no effect isn’t an adaptation, a temporary change during a storm isn’t a lasting feature, and a learned behavior isn’t a structural trait. The defining idea is a built-in body feature that gives a survival advantage.