What did a mercenary do during the renaissance? why does the term mercenary carry such negative associations, or connotations?

In 1912, the imperial system that had ruled over china for thousands of years

Match the following: 1. empirical the belief that an idea should be evaluated based on how it works 2. fundamentalism knowledge based on observation and experiment rather than theory 3. obtrusive to intentionally force ideas or intrude on others 4. pragmatism not religious or spiritual in nature 5. secular a religious doctrine that emphasizes a return to rigid principles

The information box says that the han added 4,000 miles of wall. refer to the mileage scale. how can this be true?