sentences: keeping warm is the opposite of becoming cold & if a living thing becomes too cold then that living thing will die ->  an animal requires warmth for survival  an animal requires warmth for survival & if the environmental temperature / air temperature is too cold then an animal / a living thing in that environment may become cold ->  an animal requires warmth for survival in a cold environment  an animal requires warmth for survival in a cold environment & the arctic environment usually is cold in temperature from being at a northern lattitude ->  an animal requires warmth for survival in an arctic environment  an animal requires warmth for survival in an arctic environment & humans usually develop inventions that they require ->  a human might develop an invention for warmth in an arctic environment  clothing is a kind of covering made from materials & insulated material can be used for keeping warm ->  clothing made from insulated material can be used for keeping warm  clothing made from insulated material can be used for keeping warm & if something / an invention / a discovery is invented / discovered then that something / that invention / that discovery can be used ->  if insulated clothing is developed then it can be used for keeping warm  a human might develop an invention for warmth in an arctic environment & if insulated clothing is developed then it can be used for keeping warm -> a human might develop insulated clothing for keeping warm in an arctic environment