Which of the following is an example of the interaction between the circulatory and respiratory organ systems in a human?

a.
the pancreas produces a rush of insulin when a child eats a lollipop.
b.
the toe of a standing woman hurts when a rock falls on it.
c.
the heart of a running man beats faster than the heart of a resting man.
d.
the nutrients in food are mechanically broken down in the stomach.