Answer:
All object changes are compared with a reference , which is an object that appears to stay in place.
Explanation:
In scientific experiments, the changes in the experimental object are observed by comparing the changes with a reference object. In the reference object, no changes are made and conditions are kept normal in it. For example, if we want to measure the distance of two cars from a point, the point will be the reference point from which the distance shall be measured. Hence, all changes are made by comparison from a reference object or point.