Final answer:
Limiting factors restrict population growth by causing a shift from exponential to logistic growth as a population nears its carrying capacity. option d.
Step-by-step explanation:
Limiting factors significantly influence the size of a population within an ecosystem. When a population encounters these factors, such as insufficient food supply, lack of space, or disease, it can no longer continue its exponential growth and begins to show logistic growth. This logistic growth, characterized by an S-shaped curve, indicates that the population growth rate decreases as the population size approaches the carrying capacity, which is the maximum number of individuals that the available resources can sustain without harmful impacts on the environment.
In summary, the answer to the question 'How do limiting factors most affect population size?' is B) Restrict population growth, as they prevent the population from exceeding its carrying capacity, resulting in a self-regulated equilibrium of population size.