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.
Introduction to parts of the respiratory system and their function. Respiratory system consists of the organs that help to breathe. Respiration also known as breathing is the process which delivers oxygen from the external atmosphere to the body and removes the carbon dioxide from body and expels out.The main parts of the respiratory system and their functions are as follows.1  The nostrils.ronchi: The bronchi are the two air tubes that branch off of from the trachea and carry atmospheric air directly into the lungs. Lungs: The main organ of the respiratory system is lungs. Lungs are the site in body where oxygen is taken into and carbon dioxide is expelled out.