Archaeologists have discovered iron objects at six sites in Tamil Nadu, dating back to 2,953–3,345 BCE, or between 5,000 to 5,400 years old. This suggests that the process of extracting, smelting, ...

Explain, using aluminium, gold and iron as examples, how the method used to obtain the metal is related to its position in the reactivity series and to the cost of the extraction process.