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 is the system in the human body that enables us to breathe. The act of breathing includes: inhaling and exhaling air in the body; the absorption of oxygen from the air in order to produce energy; the discharge of carbon dioxide, which is the byproduct of the process.pper respiratory tract: This includes the nose, mouth, and the beginning of the trachea (the section that takes air in and lets it out). Lower respiratory tract: This includes the trachea, the bronchi, broncheoli and the lungs (the act of breathing takes place in this part of the system).