Which fact most clearly shows the difficulty in defending the Roman empire against invasion? (1 point)
• At its height, the empire comprised nearly 1.7 million square miles of land and water.
• Over the course of its history, the Roman empire built about 55,000 miles of paved roads.
• The Mediterranean Sea stretches about 2,300 miles west to east and about 600 miles from Italy to the African coast.
• At ts height, the empire likely had a population as high as 100 million.