Hello! The interaction between the two system is an inter-dependent relationship. An example of this is that the heart pumps arterial blood to the circulation. The deoxygenated or venous blood returns to the lung where blood is oxygenated. Then the blood flows into the heart chambers and the cycle continues on.
Answer: As scientists started improving on the microscopes, the more they got to observe the cells in depth. Compound light microscope uses visible light to produce a magnified image and doesn't allow it to scatter.
Peripheral would be the answer