Question

motion is relative to a/an.... * 1 point compass. observer. reference point.

Explanation:

In physics (a subfield of Natural Science), the concept of motion being relative means that the description of an object's motion depends on a chosen reference point. A reference point is a place or object used for comparison to determine if an object is in motion. A compass is for direction, and an observer alone isn't the key; the reference point is the standard for measuring motion's relativity.

Answer:

C. reference point.