What is one of the main features of karst topography?
sinkholes
streams
springs
slumps

Karst is a topography formed from the dissolution of soluble rocks such as limestone, dolomite, and gypsum. It is characterized by underground drainage systems with sinkholes and caves. It has also been documented for more weathering-resistant rocks, such as quartzite, given the right conditions.

Option (1)

Explanation:

Sinkholes are one of the distinct geological features. These are circular depressions that are formed due to the collapse of the ground surface. These are formed in the region where the rocks are either carbonate (limestone), salt rocks or gypsum which is easily dissolved when it comes in contact with the groundwater flow. It results in the formation of caves. The sinkholes are characterized by the presence of karst topography above them on the surface and sinkholes are often considered to be one of the main features of the karst topography.

Thus, the correct answer is option (1).

water is used to store them because it would keep the radiation from getting out in the open and causing harm to the workers