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.
1 Your respiratory system is made up of the tissues and organs that allow oxygen to enter and carbon dioxide to leave your body. 2  Respiratory system organs include your nose, mouth, larynx, pharynx, lungs, and diaphragm.  During inhalation, the diaphragm contracts and moves downward, and brings air into the lungs.