How does the Rotary Gear pump operate?

The correct answer highlights that a Rotary Gear pump operates using two meshed gears to create watertight areas. This design is fundamental to the function of the pump, as the interlocking gears trap a certain volume of fluid and move it from the inlet to the outlet as they rotate. The meshing action ensures that the liquid is sealed within the enclosed spaces created between the teeth of the gears, which allows for efficient and continuous flow.

In contrast to this mechanism, a single shaft pulling water would not create the necessary positive displacement required for fluid transfer, nor would it ensure a sealed delivery of the fluid. The single piston option misrepresents the operational principle of the Rotary Gear pump, as it does not utilize a piston mechanism but rather relies solely on the rotating gears to move fluid. Lastly, gravity alone cannot be relied upon for the functioning of a Rotary Gear pump, as the pump's design specifically facilitates lifting and moving fluids against gravitational forces through mechanical action, rather than depending on gravitational flow.