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

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

: having or being atoms of greater than normal mass for that element

: 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

: a character in a story or play who opposes the hero : villain

: 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