🔍 Key Concepts

• Alloy basics – an alloy is a mixture of metals where one main metal is combined with another to change properties like hardness and resistance to corrosion. • Common copper alloys – think about which metals, when mixed with copper, give well‑known named alloys used in marine hardware (propellers, bearings, fittings). • Difference between brass and bronze – both involve copper, but each pairs copper with a different main secondary metal.

💭 Think About

• Ask yourself: in marine fittings and propellers called "bronze," which second metal is typically mentioned together with copper? • Which choice in the list is actually the pair that defines brass, not bronze? Eliminating that may narrow your options. • Of the four options, which pair have you most often heard specifically described as "bronze" in engineering, casting, or marine applications?

✅ Before You Answer

• Be clear on which copper alloy is called brass so you don’t confuse it with bronze. • Verify which pairing of metals is historically used for statues, bells, and traditional propellers, commonly labeled as bronze. • Check that the correct answer involves copper as the primary metal and a single main secondary metal, not a mix that commonly names a different alloy.