Blood is flowing through a circuit with an inflow pressure of 100 mm Hg and an outflow pressure of 10 mm Hg. Each of the parallel circuits (R1, R2, R3, R4 and R5) has a resistance of 5 mm Hg/mL/min. What is the blood flow across this circuit?
3.6 ml/min 45 ml/min 90 ml/min 135 ml/min