The pressure of an operating hydraulic system, as indicated by a pressure gauge, is a result of the fluid flow overcoming __________.

Correct Answer: Option D — all of the above

Pressure in a hydraulic system is a measure of resistance to flow. This resistance is generated by the external load applied to the actuator, the internal friction of the fluid moving through piping, and the mechanical resistance of system components. The pump creates flow; the system creates pressure.