A logistic growth occurs when there is a growth decrease once the population reaches its maximum capacity. It produces a S-shaped curve in the graph. Therefore, the population of the green lacewing has reached the carrying capacity of the field.

B. The lacewing population had reached the carrying capacity of the field.

Choice A exhibits competition with the resources between the ash trees and the maple trees, whereas choice B describes a human activity that results in a decrease in the availability of water. Choice D indicates a decrease in the population of ash trees due to deforestation, while choice E shows a decrease in the size of the habitat of ash trees. These events are considered as limiting factors that decrease the carrying capacity of the land.

Therefore, the correct answer is C. Parasitism as a limiting factor only in the population size of the ash trees. This condition only influences the population growth and density of the ash trees; hence, it does not directly affect the carrying capacity of the land.

C. A beetle that infects ash trees is introduced to the land.

When non-native or invasive species were introduced into a new environment, their population grow very quickly due to the lack of predators or parasites that control them. Since no other species attack them, their mortality or death rate is very low, while their birth rate grows exponentially due to the abundance of resources in the environment. If this pattern continues, the native species in this environment could be out-competed by the new species in terms of the resources that they consume and the existing biodiversity in the lake ecosystem may be threatened or harmed.

C. The introduction of nonnative fish species that has no natural enemies in the lake.

The hunting habits of humans are considered as an act of predation. Humans usually attack adult prey, which in this case is the bison, in large numbers. Since only the adult bisons have the ability to reproduce, attacking them would mean that they can no longer reproduce offspring. Therefore, this action pushes the population of the prey to decline dramatically.

D. Human hunters replaced the natural predators of the bison.