Which feature distinguishes the entrance of Niagara Cave?

The feature that distinguishes the entrance of Niagara Cave is that it has one way in and one way out. This design is significant because it creates a unique experience for visitors, allowing them to explore the cave in a linear fashion, ensuring that they follow a guided path through its various formations and features. Having a single entrance and exit helps in managing the flow of visitors, enhancing safety and ensuring that tours can be efficiently conducted without the risk of disorientation within the cave system. This setup also allows for a more controlled environment in terms of lighting and temperature, providing a more immersive experience as visitors navigate the cave's passages.

The other choices touch on features that are not characteristic of Niagara Cave. For instance, multiple entrances would complicate the visitor experience and management; surface-level access is not a defining trait, as many caves have varying depths; and accessibility from nearby lakes is not specific to Niagara Cave, as it mainly emphasizes its unique geological features and guided tour experience.