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 primary function of the respiratory system is to provide oxygen to every part of the body through the process of inhaling oxygen and exhaling carbon dioxide. The respiratory system consists of tissues and organs inside the body that allow people to breathe. This system includes blood vessels, the lungs, airways and certain muscles. The major airways of the respiratory system include the nose, windpipe, mouth, bronchial tubes and larynx.