Liebig's Law of the Minimum

An ecological/physiological principle stating that an organism's growth, performance, or population size is constrained by the scarcest essential resource (the limiting factor), not by the total sum of available resources.

An ecological principle stating that an organism’s growth, yield, or performance is constrained by the essential resource that is in the shortest supply relative to its requirement; adding more of non‑limiting resources does not increase performance until the limiting resource is increased.