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.
Human anatomy is important to study to help explain how organs and other structures of the body work. There are eight systems in the human body. Each system relies on the other to keep the body functioning. The systems of the body includes the circulatory, immune, skeletal, excretory, muscular, endocrine, digestive, nervous and respiratory. It is important to understand how human body systems work together. The following is an explanation of how each body system works and the purpose of it.