Refer to figure. The diagram represents top-down control of two food webs with three trophic levels.The food web represented on the left includes omnivores, and the one on the right does not.Which effect of omnivores most directly results in the decreased size of the primary producer level shown on the left?
A) Competing with other omnivores
B) Competing with primary producers
C) Feeding on primary consumers
D) Feeding on primary producers
E) Preying on top carnivores

Question

Refer to figure.  The diagram represents top-down control of two food webs with three trophic levels.The food web represented on the left includes omnivores, and the one on the right does not.Which effect of omnivores most directly results in the decreased size of the primary producer level shown on the left?
A) Competing with other omnivores 
B) Competing with primary producers 
C) Feeding on primary consumers 
D) Feeding on primary producers 
E) Preying on top carnivores

Quizplus · Accepted Answer

Omnivores feeding on primary producers directly decreases the size of the primary producer level in the food web, as they consume plants and algae that are the foundation of the food web. Competing with other omnivores or primary producers would not directly result in a decrease in the primary producer level, and feeding on primary consumers or preying on top carnivores would not directly affect the primary producer level.

Refer to Figure