Final answer:
The statement is describing a density-dependent limiting factor where sea otters are competing with starfish for sea urchin food.
Step-by-step explanation:
The statement 'Sea otters are competing with starfish for sea urchin food' is describing a density-dependent limiting factor.
In this case, the availability of food (sea urchins) is directly affected by the density of the sea otters and starfish populations. As the population of sea otters and starfish increases, the competition for the limited food resources (sea urchins) also increases.
This is an example of intraspecific competition where individuals of the same species (sea otters and starfish) compete for resources.
Learn more about Density-dependent and density-independent limiting factors