Read this excerpt from A Black Hole Is NOT a Hole. Acting on the hint, scientists search the X-rays for patterns that most likely signal black holes. One pattern is an X-ray ring that seems to surround nothing. The nothing part might be a black hole. If so, the ring is energy released by super-heated matter spiraling just outside the event horizon. Which statement best identifies the type and use of description? The word is signals a characteristic of an X-ray pattern. The phrase most likely signals an example of an X-ray pattern.