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 a group of organs responsible for carrying oxygen from the air to the bloodstream and expelling the waste product carbon dioxide.The main parts of this system are the airways, the lungs and linked blood vessels, and the muscles that enable breathing.The airways are passages that carry oxygen-rich air to the lungs and carbon dioxide out of the lungs.The airways include the: Air first enters the body through the nose or mouth, which wets and warms the air. (Cold, dry air can irritate the lungs.) The air then travels through the larynx and down the trachea.he airways are passages that carry oxygen-rich air to the lungs and carbon dioxide out of the lungs. The airways include the: Air first enters the body through the nose or mouth, which wets and warms the air. (Cold, dry air can irritate the lungs.) The air then travels through the larynx and down the trachea.