Question

What are the magnetic field lines made up of?

Answer 1

magnetic field lines are the imaginary lines which tell us about the area of its existence and it is the graphical representation of the magnetic fiels

Answer 2

Here is your answer.

A reason around a magnetic material or moving electric charge within which the force of magnetism acts.

A magnetic field is a vector field that describes the magnetic influence of electrical current and magnetic material.

I hope this helps you.