what do the following have in common? indentured servants
indigenous
slaves
Indentured servants are people who voluntarily work for someone to pay off their debts. Slaves work involuntarily.
Check this definition of indigenous.
http://www.google.com/webhp?source=search_app#hl=en&q=indigenous&tbs=dfn:1&tbo=u&sa=X&ei=VKZfULCmGMPxygGXrYGIDA&ved=0CBwQkQ4&bav=on.2,or.r_gc.r_pw.r_qf.&fp=99d6414d69e5a888&biw=711&bih=453
A few indigenous peoples were forced to work as slaves.