What is an alloy?

An alloy is defined as a mixture of two or more metals or a metal and another element. This combination is typically done to enhance certain properties, such as strength, corrosion resistance, or ductility, which can be achieved through altering the composition and structure of the metals involved. Alloys can have significantly different physical and chemical properties compared to the individual metals that compose them.

For example, steel, which is an alloy of iron and carbon, is much stronger and more durable than pure iron. By understanding that alloys are fundamentally mixtures, it becomes clear why the definition aligns with option A. Alloys are integral to many applications in engineering and construction, where specific material attributes are necessary for performance and reliability.

The other options do not accurately define what an alloy is. A pure metal with higher conductivity does not relate to the concept of mixing metals, nor does a single metallic element, which describes a distinct substance rather than a composite material. Similarly, a type of plastic used in construction does not pertain to metallurgy or the properties of metals and alloys.