What underground phenomenon can be commonly found in limestone caves?

The underground phenomenon that is commonly found in limestone caves is best represented by stalactites and stalagmites. These formations result from the deposition of minerals, primarily calcite, which is precipitated from dripping water that has seeped through the cave's ceiling. As water drips, it leaves behind mineral deposits that build over time to create these iconic structures.

While fossil remains can sometimes be found in caves, they are not exclusive to limestone caves and represent a different geological or paleontological interest rather than a consistent phenomenon in such environments. Mineral deposits are indeed prevalent, but they often refer to general deposits of various minerals and do not specifically highlight the dramatic scenery associated with stalactites and stalagmites. Insulation from external temperature fluctuations can occur in cave environments but is more a characteristic of the cave as a whole rather than a phenomenon created by specific geological processes or formations.

Therefore, the presence of stalactites and stalagmites is a defining feature of limestone caves, showcasing the unique environmental and geological processes at play in these fascinating subterranean realms.