The carrying capacity for a species in an ecosystem is primarily determined by a. the species’ fertility b. the number of predators c. the ecosystem’s resources d. a boom-and-bust curve

  C; the ecosystem’s resources

Explanation: The carrying capacity of a biological species is the maximum number of individuals that a given environment can sustain indefinitely.

This number depends on the disponibility of things like the necessities of the species, like water, food, habitat and other things. Those things are the resources of the environment/ecosystem.

Then the correct answer is option C; the ecosystem’s resources