Final answer:
Katydids have adapted to look like leaves as a form of camouflage to evade predators, thereby gaining a survival advantage.
Step-by-step explanation:
Katydids are insects that utilize their physical appearance for camouflage to blend into their surroundings, specifically looking like leaves. This adaptation serves primarily as a means of avoiding detection by predators. Mimicry and camouflage are evolutionary traits that provide a survival advantage to species like katydids, making it difficult for predators to spot them when they are stationary. While there might be other benefits, such as hunting or environmental resistance, the primary advantage of looking like a leaf for a katydid is camouflage from predators.