Final answer:
The position of 0 represents the surface of the pond. When the position is recorded as 0, it means the duck is at the surface of the pond.
Step-by-step explanation:
The position of 0 represents the surface of the pond. Since the duck is 2 feet below the surface, its position can be recorded as -2 feet. When the position is recorded as 0, it means the duck is at the surface of the pond.