Ferrous metals are defined as metals that contain which element?

Ferrous metals are characterized by their iron content. The presence of iron is what differentiates ferrous metals from non-ferrous metals. This group includes metals like steel and cast iron, which are widely used in construction and manufacturing due to their strength and durability. Iron is pivotal in determining the properties of ferrous metals, such as their magnetic characteristics and resistance to corrosion when compared to other metals.

The other options, while they represent different types of metals (aluminum, copper, and zinc), do not contain iron as a principal element and thus do not fall into the category of ferrous metals. Non-ferrous metals, which include aluminum, copper, and zinc, are known for their resistance to corrosion and various other applications, but they lack the significant iron content that defines ferrous materials.