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.
In fact, the system is composed of the following biological structures: nose and nasal cavity, mouth, pharynx, larynx, trachea, bronchi and bronchioles, lungs and the muscles of respiration. (1) A properly functioning respiratory system is a vital part of our good health. Respiratory infections can be acute and sometimes life threatening.