How do the digestive, circulatory, respiratory and excretory systems provide the body with nutrients and energy?
Every cell in the body needs energy to perform its duties and stay alive. Cells use energy when they have the nutrients they need to perform.
The digestive system converts bulk foods like bread and meat into their components, and absorbs them into the bloodstream through the intestines. The circulatory system moves the nutrients from the intestines to the cells that need them.
The respiratory system provides the oxygen necessary for cells to metabolize, and the circulatory system moves the oxygen around the body and to the cells.
The excretory system and respiratory system both get rid of waste products. The excretory system disposes of all food not absorbed by the body, and any foods that the digestive system couldn't break down. The respiratory system removes carbon dioxide, a waste product of the cell, from the circulatory system.