Why is Khadar soil renewed repeatedly?

Correct answer: Due to new alluvial deposits laid by rivers during floods

Khadar is the newer alluvial soil found mainly on river flood plains. Rivers carry fine particles such as silt, sand and clay from higher areas. During floods, the river spreads over nearby land and leaves a fresh layer of these materials when the water level falls. This repeated addition keeps Khadar comparatively young and often replenishes nutrients, making it generally fertile.

Option A is correct because repeated flooding brings new alluvial deposits and renews the soil. Coral grows in marine environments and does not create the alluvium of northern flood plains. Glaciers do not form in deserts as the normal cause of Khadar renewal, and volcanic lava is unrelated to ordinary river deposition. The key chain is flood, transport of sediment, deposition on the flood plain and renewal of Khadar. This also distinguishes Khadar from older alluvium, which is called Bhangar.