How was chinas Middle Kingdom concept and how does it relate to their tribute system?

The national college football team hampionship this year will be contest

How have the government regulations changed the use of child labor since the 1800s

    which of the following was anecological  result of european exploration from 1400 to 1800?   a.  increased trade with east asia      b.  the spread of epidemic diseases      c.  expansion of english territory      d.  the spread of christianity