In simple it is our surroundings or the things that surround us.
  BIO PHYSICAL: The physical & biological factors along with the chemical interactions that affect an organism where pollution is important.
SYSTEM: the surrounding of physical system that my interact with systems by exchanging mass,energy and other properties.
               so the main thing is that making use of those things . only foolish will destroy those things. for example take trees we cutting down them but they gives us a lot that is uncountable  . so now a days we are becoming as foolish . so if we make use of them they provide all that are required for life .
Environment is always helping us to survive It is all of it that surrounds us....