Given the task definition and input, reply with output. Given a scientific passage and an answer, generate a question for the given answer.

Passage: Whales and bats have the trait of echolocation. This is the ability to locate objects in the dark by bouncing sound waves off them. The most recent common ancestor of whales and bats did not have this trait. Apply lesson concepts to explain how the trait evolved in whales and bats. Answer: echolocation
What term is defined as the ability to locate objects in the dark by bouncing sound waves off them.