What is called a resource so scared that a limits the size of a population?

A resource that is so scarce that it limits the size of a population is called a "limiting resource." This resource can include essentials such as food, water, shelter, or other necessities that are in short supply. When the availability of these resources decreases, the population size is constrained, leading to competition among individuals for survival. Limiting resources play a crucial role in regulating population dynamics and ecosystem balance.