Circulatory System (Cambridge O Level Biology)

To reduce the pressure of blood returning from the lungs, in order to supply cells of the body most efficiently with the reactants for respiration.

To increase the pressure of blood sent to the lungs, in order to supply cells of the body most efficiently with the reactants for respiration.

To increase the pressure of blood returning from the lungs, in order to supply cells of the body most efficiently with the reactants for respiration.

To reduce pressure of blood sent to the lungs, in order to supply the cells most efficiently with the products for respiration.