1 An unopened container should last for 1-3 months at 40Â°F or less in the refrigerator, but some companies guarantee their product for up to 6 months.  If left in its partially-open original paper wrap, the exposed area of stick butter will begin to harden and smell stale after about a week, as oxygen sets in.
Quick Answer. Humans need a respiratory system because it is made up of organs that allow them to breathe. Breathing delivers oxygen to the body and takes away carbon dioxide. Every cell in the body needs oxygen to obtain energy from food. Continue Reading.
The respiratory system functions in the exchange of gases between the body and the environment. Together with the other organ systems they also contribute to hemostasis-that is, to maintaining internal operating conditions for all of the body s living cells.1  The Nature of Respiration.2  The Basis of Gas Exchange.he respiratory system functions in the exchange of gases between the body and the environment. Together with the other organ systems they also contribute to hemostasis-that is, to maintaining internal operating conditions for all of the body s living cells. 1  The Nature of Respiration. 2  The Basis of Gas Exchange.