Approximately how old is Niagara Cave?

Niagara Cave is estimated to be approximately 2.5 million to 10,000 years old, making it a significant geological feature formed during the Pleistocene epoch. This time frame corresponds to the last glacial period, during which the processes of erosion and deposition played a crucial role in shaping the cave's structures. The age suggests that the cave has undergone extensive changes over millions of years, reflecting natural events such as glacial activity and the melting of ice that contributed to the formation and development of underground systems and features.

The other options do not encompass the extensive geological timescale that accurately represents the cave's history, as they suggest a much shorter timeframe that does not align with the scientific understanding of cave formation in this region.