As an energy source, such energy comes from the sun collected and stored using mechanical pumps or fans to circulate heat-laden fluids or air between solar collectors and a building.

The space within which the concentration of a pheromone (or any other behaviorally active substance) is at or above threshold concentration: The active space of a pheromone is, in fact, the signal itself, for example the signals of light and sound.

In cells, the use of energy to move substances, usually molecules or ions, across a membrane: Active transport requires the application of energy in metabolism and is supported by pumps, or also known as carrier proteins.