What were some of the key building materials of the Colosseum?

• A. wood, lime, straw
• B. stone, iron, clamps
• C. glass, concrete, steel
• D. earth, timber, brick

Answer: (B)

The main idea is that ancient Roman amphitheaters like the Colosseum relied on heavy stone work bound together with metal connectors, complemented by a concrete core. The Colosseum’s exterior and much of its load-bearing structure were built with stone, and the Romans used iron clamps to connect and secure these stone blocks. This combination—stone for the durable exterior, metal clamps to hold blocks in place, and concrete within for a strong, lightweight core—enabled the scale and stability of the structure. The other options introduce materials not characteristic of the Colosseum’s core construction (such as modern steel, or materials like glass and timber in significant roles), making stone, iron, and clamps the best fit for describing its building approach.