place heavy demands on

:  physical environment :  space

:  a way for admission or transit

:  physical surroundings :  atmosphere

:  to put in or as if in a particular place or position :  set

:  to present for consideration

:  to put in a particular state

:  having great weight

:  characterized by mass or weight

:  having a high specific gravity :  having great weight in proportion to bulk

:  to a great or overwhelming degree :  with or as if with great weight :  in a heavy manner :  heavily

:  heavyweight

:  a theatrical role of a dignified or somber character

:  an actor playing such a role

:  an act of demanding or asking especially with authority

:  something claimed as due or owed

:  question

:  to call for something in an authoritative way :  to make a demand :  ask

:  to ask or call for with authority :  claim as due or just

:  to call for urgently, imperiously, or insistently