Separation technique using multiple partitions.

Ocean current flowing opposite trade winds.

(CCC, also counter-current chromatography) a form of liquid–liquid chromatography that uses a liquid stationary phase that is held in place by inertia of the molecules composing the stationary phase accelerating toward the center of a centrifuge due to centripetal force and is used to separate, identify, and quantify the chemical components of a mixture.

Gradient amplification mechanism in kidneys.

A countercurrent mechanism system is a mechanism that expends energy to create a concentration gradient.

Heat or substance transfer mechanism.