Definition of theme - Environment

http://dictionary.reference.com/browse/environment : the air, water, minerals, organisms, and all other external factors surrounding and affecting a given organism at any time.
external - temperature, food etc.


http://onelook.com/?w=environment&ls=a : the area in which something exists or lives
exists - alive, living things; able to live.
e.g. plants, animals etc


http://www.thefreedictionary.com/environment : the external surroundings in which a plant or animal lives, which tend to influence its development and behaviour
development and behaviour- what the plant or animal would grow into and what they would behave like when growing or when matured. 
eg. animals : develop a keen sense of hearing. always going solo in hunting. the animal probably lives in an area where many predators thrive. it would then need to develop a keen sense of hearing to watch out for its predators. food is probably scarce and thus, it prefers to go hunting alone - more food.




after reading the definitions from different sources, 
MY DEFINITION/CONCLUSION/SUMMARY :environment - A place in which a living thing lives, with different factors in the surroundings affecting it.