Answer:
The correct answer is "d. An increase in the number of predators that feed on it." This statement suggests that the number of predators feeding on the ecosystem is not a possible cause for the increase in predator population. However, it is important to note that the growth in predator population can indeed be influenced by an increase in the number of predators that feed on the prey. When the number of predators feeding on the ecosystem increases, it can lead to competition for resources and, in turn, potentially limit the growth of the predator population. Therefore, option d is not correct, as an increase in the number of predators that feed on the prey can contribute to the growth of the predator population.