Passage:
[1] Modern engineers have long marveled at the durability of ancient Roman concrete structures, which have survived for millennia in harsh environments. [2] Recent chemical analyses reveal that the secret lies in "lime clasts," small white mineral chunks previously dismissed as evidence of poor craftsmanship. [3] When cracks begin to form in the concrete, water seeping into the fissures dissolves the calcium within these clasts. [4] This dissolved calcium then recrystallizes, effectively sealing the cracks and preventing further structural damage.
The writer wants to add a sentence after sentence 1 that provides the most specific, concrete evidence of the durability of these ancient structures. Which of the following sentences would best accomplish this goal?
- For example, the Pantheon's massive concrete dome, built in the second century CE, remains entirely free of reinforcing steel yet shows no major structural cracks today.Answer
- BMany harbors, monuments, and temples constructed by Roman builders are still standing throughout Europe and the Mediterranean.
- CBecause the massive sea walls at the ancient harbor of Cosa have endured constant wave action for over two millennia.
- DEngineers have spent years studying the chemical composition of these ancient materials to see if they can replicate them today.