Top predators impact ecosystems by controlling:
“Population size of prey” for top predators impact ecosystems by controlling. This relationship follows from the ecological mechanism represented by the terms in the item, not merely from an association between their names. Evidence should connect encounter rates or resource use to survival, growth, or reproduction. The ecological label follows that causal effect rather than superficial proximity between organisms. The remaining alternatives—“Nutrients”, “Primary productivity”, “Abiotic factors”—refer to different states, processes, or scales and therefore do not express the same causal relati
Ref: Fundamentals of Ecology, Odum & Barrett, 5th Ed., Ch. 4