Which term refers to the largest number of individuals of a population that an environment can support?

The term that refers to the largest number of individuals of a population that an environment can support is "Carrying Capacity." This concept is fundamental in ecology and represents the maximum sustainable population size of a species given the resources available in the environment. It takes into account various factors such as food availability, habitat space, water supply, and other necessary resources that support population growth and survival. When a population exceeds its carrying capacity, it can lead to overconsumption of resources, habitat degradation, and ultimately a decline in population due to increased mortality or decreased reproduction rates.

The other options describe related concepts but do not capture the specific definition of the largest sustainable population size. For example, "Population Limit" is not a widely recognized term in ecological literature, and while "Environmental Threshold" refers to levels beyond which there are significant changes in ecosystem health or function, it does not specifically denote population size. "Resource Availability" describes the presence of necessary resources for a population but does not directly indicate the maximum population size that can be sustained by those resources.