Final answer:
The sea palm can persist in shoreline areas with the presence of a superior competitor, Mytilus, due to periodic disturbances, according to Paine's studies.
Step-by-step explanation:
Based on Paine's studies, the persistence of the sea palm in shoreline areas despite the presence of a superior competitor, Mytilus, is primarily due to periodic disturbances. These disturbances disrupt the dominant competitive pattern that would typically lead to the superior competitor (Mytilus) monopolizing resources.
Instead, it creates opportunities for less competitive species, such as the sea palm, to establish and maintain a presence in the ecosystem. The other options given, such as allelopathy, character displacement, and competitive exclusion, do not directly relate to the mechanism that allows for this persistence according to Paine's findings.