The undigested waste products does not enter your body cavity. That is called as faecal matter. Scientifically speaking the food you eat is not "Inside" your body cavity. It is always "Outside" the body cavity. You go for extracellular type of digestion. I found it very difficult to teach the same in my dental college class.
Always! you need the process of the circulatory system in order to breathe and exhale waste.
Everything in the circulatory system works together to remove waste from the blood. The circulatory system provides the excretory system with the blood to be cleaned.
The primary goal of the urinary system is the elimination of waste from the body processes. If these wastes are not removed, they may become toxic to the system. The circulatory system deposits the waste for the urinary system to remove.
Circulatory system.
The circulatory system imports oxygen and exports waste materials or carbon dioxide. The circulatory system distributes fresh oxygen to the tissues and organs of the body.
The purpose of the digestive system is to break down food into nutrients and waste. The nutrients nourish the body, the waste is sent through the excretory system.
The Circulatory system is a busy system because it can never stop. Your circulatory system is what pumps your blood and gives your cells food water and oxygen and takes waste away from your cells. If your circulatory system ever stopped then you would die.
Circulatory system
The circulatory system transport oxygen and respiratory material (food) to the billions of our body cells.
"circulatory"
Three examples would be: -digestive system, where nutrients enter the bloodstream -endocrine system, where hormones enter the bloodstream -immune system, where blood, organs, tissues, cells, and cell products work together to respond to dangerous organisms that enter the body. (taken directly from http://www.factmonster.com/ipka/A0774536.html)
delivers oxygen and nutrients, removes waste