Nervous system and Circulatory system
The circulatory system gives blood to your nervous system so you can use you 5 scenes. You hot and cold receptors which are parts of your nervous system, can help you know if you are touching something that could burn you or give you frostbite. They would not work without your circulatory system.

Circulatory and Respiratory
The main function of the respiratory system is to provide the body oxygen which all cells need to produce energy, The circulatory system then transfers the oxygen to all the cells in the body via red blood cells. The Respiratory system has 3 main parts, the Bronchus, Alveoli and the lungs itself. There is a certain muscle under the lung that makes the lungs get bigger and smaller it is called the Diaphragm.


Digestive and Circulatory
The circulatory system brings oxygen to the digestive system so the digestive system can break down food to get nutrients. Then the nutrients gives us energy so the body has some energy to pump the blood to the circulatory system. That just keeps going in a circle until you die.


Circulatory and excretory
The main function of the excretory system is to get rid of nitrogenous wastes, which are toxic to the body. Kidneys filter blood brought to them by the circulatory system. We get rid of nitrogenous waste through urine and sweat. This helps us maintain homeostasis. (Stable internal environment)


Nervous and Skeletal
The Nervous system transports messages throughout the body from the brain. The messages are carried by neurons. The Sensory neurons send messages to your senses, the interneurons connects your nerves and the the motor neurons receive messages.


Nutrients+Oxygen=Energy+CO2+ Nitrogenous Waste
It is cellular respiration. The nutrients come from the digestive system and energy and Co2 come from the Respiratory system. Nitrogenous waste comes from the Excretory system. The circulatory system brings all of this together and all of these things are burned it the mitochondria.