Final answer:
As per Laplace's Law, as the diameter (or radius) of a blood vessel increases, the force applied to the wall of that vessel also increases. This is observable throughout our circulatory system, where factors such as vessel size and blood pressure are adjusted to regulate blood flow, (option A) increases.
Step-by-step explanation:
According to Laplace's Law, as the diameter of a blood vessel increases, the force applied to the wall of the vessel increases (option A). This is because the force acting on the wall of the vessel is determined by blood pressure and the diameter (or radius) of the vessel. This principle can be seen in action within our circulatory system, where variations in vessel size and blood pressure regulate blood flow. For instance, during vigorous exercise, blood vessels supplying muscles and organs dilate (increase in diameter) leading to increased blood flow. The reverse is also true, as decreases in vessel diameter (as might be caused by arterial plaques) can reduce blood flow substantially. The resistance to blood flow in a vessel is inversely proportional to the fourth power of the vessel's diameter, due to the Laplace's Law.
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