Miguel’s presentation on the Iron Age moving into the Middle Ages was detailed. He outlined the process of smelting and clarified how metals such as copper, tin, and bronze could be combined with intense heat to create strong iron. He added some images of tools that came into wide use, such as adzes and axes and even armor. Miguel left out one tool, however, that was highly important to the civilization’s progress. What might have been that tool, and why is it important?

A.
hammer, invaluable for building homes

B.
drinking vessel, essential for carrying water

C.
fencing, to create separation between properties

D.
heavy plough, which advanced food production