Answer:
threshold effect.
Step-by-step explanation:
Threshold effect: The term threshold effect is defined as a phenomenon that experiences a radical and sudden change that generally occurs after a remarkable quantitative limit which is referred to as a threshold. It often refers to the renormalization group i.e, the threshold effect.
Threshold refers to the minimum number of a population to get benefited with something in a particular area.
In the question above, the given scenario is an example of a threshold effect.