What does blue coloring represent?

The structure/s that keeps blood flowing in one direction.

What structure separates the left and right side of the heart?

Does the brain require the movement of blood through veins, arteries, and capillaries?

Does the heart beat as one whole beat or with two individual beats?

Which direction, in reference to the heart, do veins carry blood?

Which direction, in reference to the heart, do arteries carry blood?

Select all of the common blood types in humans.