2. Explain why the magnetic field would not be unique (that is, not have a single value) at a point in space where magnetic field lines might cross. (Consider the direction of the field at such a point.)

Magnetic field would not be unique at a point where they cross each other because the magnetic field will seem to have two different directions which is not possible. The magnetic field lines at any point in space are tangential to the direction of the magnetic field. As a result magnetic field lines are tangents to the magnetic field. When two magnetic field lines intersect, there will be two directions for the same magnetic field at the point of intersection which is impossible. As a result the magnetic field cannot be unique if this were possible.

well clustered together.

points close on a scatter diagram