The Romans revolutionized architecture by utilizing the arch and innovations in materials, allowing them to create taller and more durable structures. Their use of concrete and vaulting techniques enabled them to design monumental buildings like the Colosseum. As a result, Roman engineering has had a lasting influence on architecture and construction methods throughout history. ;
The Romans built taller structures primarily due to their use of the arch, which allowed for better weight distribution and larger openings than previous techniques. Together with their mastery of concrete, this innovation enabled the construction of monumental buildings like the Colosseum. Therefore, the correct answer is A. Arch.
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