In ecological terms, what limits the growth of a population?

The correct answer, which cites carrying capacity, refers to the maximum number of individuals of a particular species that an environment can sustainably support. This concept is crucial in ecology because resources such as food, water, space, and shelter can be limited. When a population approaches its carrying capacity, factors such as increased competition for resources, higher mortality rates, or decreased birth rates may occur, which help regulate the population size.

While the other choices like symbiotic relationships and resource competition also play important roles in population dynamics, they are not comprehensive enough to address the overarching limit on population growth. Symbiotic relationships can enhance or inhibit populations depending on the nature of the interaction but do not singularly determine the population size. Resource competition undoubtedly influences growth rates as it can limit available resources, but it is a part of the broader concept of carrying capacity.

Thus, carrying capacity encapsulates various environmental factors that collectively limit population growth, making it the most accurate answer to the question regarding what limits the growth of a population.