Final answer:
For ferromagnetic materials to become magnetized, the magnetic moments of electrons within the atoms must align with each other, particularly within regions called domains.
Step-by-step explanation:
In order for a ferromagnetic material to become magnetized, these electrons must align their magnetic moments. This is because individual electrons have a magnetic moment, and in ferromagnetic materials like iron, these magnetic dipoles become aligned within regions called domains. When an external magnetic field is applied, the domains grow and their magnetic moments align more completely, contributing to the overall magnetization of the material. This magnetization can become permanent with various processes, including heating and cooling or by applying mechanical force.