One of the most common plants in Atlantic salt marshes is cordgrass. Periwinkle snails cling to the top of tall cordgrasses during high tide. The tall cordgrasses provide protection from the snails’ predators, such as the blue crab. While the snails do not feed directly on the cordgrass, the snails can damage the cordgrass when they graze on algae and fungi that grow on the grasses. If the snail population grows too large, it can decrease cordgrass growth.

Question
Based on the passage, which of the following describes the ecological role that cordgrass serves for the snails?

Responses

Cordgrass is a biotic factor for the snails because it is the snails’ main food source.

Answer A: Cordgrass is a biotic factor for the snails because it is the snails’ main food source.
A

Cordgrass is a biotic factor for the snails because it is a living source of protection in the Atlantic salt marshes for the snails.

Answer B: Cordgrass is a biotic factor for the snails because it is a living source of protection in the Atlantic salt marshes for the snails.
B

Cordgrass is an abiotic factor for the snails because it provides habitat for the snails and crabs.

Answer C: Cordgrass is an abiotic factor for the snails because it provides habitat for the snails and crabs.
C

Cordgrass is an abiotic factor for the snails because it produces algae and fungi for the snails.