Does the density of aluminum ever change?

As long as the aluminum is pure, then the density cannot change. Aluminum is an element, and density is an identifying factor for elements because it is based on the atomic structure of the material. If you created an aluminum compound like aluminum oxide, then the density would be different

Answer;

B. with longer vectors

Explanation;Motion maps can represent position, velocity and acceleration of an object or a body at various time intervals. They are a visual way to represent an object's motion at various time.Constant velocity is indicated by; constant displacement between two points, and arrows of equal length indicating the velocity of the object.If the velocity increases then the arrows representing the velocity will be longer and displacement between the points will be greater.Therefore, longer vectors indicates greater velocity while shorter vectors indicates less velocity.