TO PEOPLE WHO HAVE THIS ASSIGNMENT:

The answer is below:

A red blood cell that’s just returned from delivering oxygen and brought back carbon dioxide would be in the right atrium. When the atrium contracts, the cell is pumped into the right ventricle. When that ventricle contracts, the red blood cell is pumped out of the heart through the pulmonary artery to the lungs.In the lungs, the red blood cell enters tiny blood vessels that come into close contact with the walls of the alveoli air sacs of the lungs. The carbon dioxide in the red blood cell passes through the walls into the alveoli while the oxygen in the alveoli air passes into the red blood cell. The red blood cell then returns to the heart via the pulmonary vein.From the pulmonary vein, the red blood cell enters the left atrium of the heart and then the left ventricle. The red blood cell is pumped out of the aorta artery and eventually reaches the capillaries leading to the individual cells. There the cells absorb the oxygen from the red blood cell and pass on their waste carbon dioxide. The red blood cell returns to the right atrium of the heart via the veins to complete the cycle.

The circulatory system transports blood and other materials into the lungs and blood vessels.The circulatory system works with the respiratory system to make sure that oxygen-rich blood can flow through the body.
The respiratory system is where gas exchange occurs in the heart, arteries, veins, and capillaries.The respiratory system supports your circulatory system with air, or more specifically oxygen, which is sent to other organs from the arteries.

Here is an example:
My model is different from the actual system because I didn’t include the lungs and it is not the real thing. It is also different because in real life, the heart would not be cut in half.Some of the limitations of a model are that it doesn't move like a real heart would and you wouldn’t be able to see it in action.