Answer:
B. Both mussels and barnacles live in the tidal ecosystems.
Explanation:
Mussels are <u>small bivalve molluscs that are adapted to both marine and freshwater ecosystems</u>. Barnacles, on the other hand, <u>are arthropods that are adapted to marine ecosystems. However, both are adapted to shallow and </u><u>tidal</u><u> zones</u>.
Both organisms are small and have the capacity to live in tidal ecosystems where they thrive and play important ecological roles. For instance, barnacles are filtering organisms, which is extremely important for the food chain, and mussels filter out significant amounts of excess nutrients and metals, that is, they make the water more suitable and clean for organisms to live.
As they are both adapted to tidal ecosystems, this would be an example of an adaptation that allows similar species, in this case mussels and barnacles, to live in the same environment.