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).

alkaline metals are lithium, sodium, rubidium, potassium, cesium and francium.

alkali metals have electronegativity from 0.7 to 1, lowest in periodic table of elements, which means that alkali metals (i group in periodic table) has positive oxidation number in compounds.

electronegativity is a chemical property that describes the tendency of an atom to attract a shared pair of electrons towards itself.

alkaline metals (far left in main group) have lowest ionizations energy and easy remove valence electrons,

for example, potassium is the alkali metal and has a single valence electron in the outer electron shell.

electron configuration of potassium is: ₁₉k 1s²2s²2p⁶3s²3p⁶4s¹.

they can not exist alone in nature, because they are very reactive.

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