WHICH WORD HAS THE ROOT WHICH MEANS PLACE, SET?

Position:

http://www.etymonline.com/index.php?term=position

=)

My guess is plant

The root is actually -pos- as in

position
impose
posit
depose
deposit
proposition
propose
disposable
dispose
disposition
etc.

You can also go to www.onelook.com and enter *pos* and find all kinds of results. Click on the one for -pos and you'll find more.

=)