Final answer:
The detail that best supports the fact claim that Marco Polo traveled East is the arduous and dangerous nature of the journey from Italy to China that would have taken months or years by foot, camel, or ship.
Step-by-step explanation:
The detail from "Did Marco Polo Really Go to China?" that best supports the fact claim that Marco Polo did travel East is: To travel so far from Italy took dangerous months or years by foot, camel, or ship. This detail highlights the arduous journey that Marco Polo would have had to undertake in order to reach China from Italy, suggesting that he did indeed travel to the East. The difficulty and length of the journey serve as evidence of his travels to China.
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