What is a common characteristic of tidal islands like Mont-Saint-Michel?

Tidal islands, such as Mont-Saint-Michel, are characterized by their temporary submersion during high tide and exposure during low tide. This unique feature occurs because these islands are situated close to shorelines and are connected to the mainland by narrow causeways that become flooded at high tide, making them inaccessible by land. Therefore, the correct characteristic emphasizes the interplay between tidal dynamics and the geography of these islands, illustrating how they essentially transform based on sea levels.

Other characteristics noted in the choices—such as volcanic activity, semi-permanent land connections, or locations in freshwater lakes—do not apply to tidal islands like Mont-Saint-Michel. Volcanic islands are formed through different geological processes, and a semi-permanent land connection would indicate a different scenario than that of a tidal island. Additionally, tidal islands are typically found in coastal marine environments rather than freshwater lakes, which further highlights why the submersion during high tide is a defining characteristic of these landforms.