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.
This helps the respiratory system because the lungs need nutrients. The respiratory system helps the digestive system by giving oxygen to the digestive system.Another basic, but important system is the skeletal system. The skeletal system is very important. This system is responsible for protecting the inner body. The skeletal system is like a metal shield covering the body.