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.
All living things have a respiratory system, including plants and animal life. The differences are mostly the difference in parts, such as lungs, trachea, bronchi, and diaphragm. The most important part of the respiratory systems are the lungs. Lungs take in oxygen and release carbon dioxide which allows us to breath.The trachea is located somewhere near our throat, and it filters the air we breathe in and branches or sends it to the bronchi.ur Cardiovascular Systems are closed, which means that blood never leaves the network of blood vessels or the blood network. While the Cardiovascular System is closed, our Lymphatic System is open. Information I Have Learned. The Circulatory System is made up of the Lymphatic System and the Cardiovascular System.