What main change in water condition is seen from Bhabar toward Terai?

Correct answer: Water sinks in Bhabar and comes near surface in Terai

The direct answer is A. Bhabar and Terai form a sequence along the Himalayan foothills, but their water conditions differ because of soil and surface materials. Bhabar contains coarse pebbles and porous deposits. Streams descending from the mountains often disappear underground there, so water sinks below the surface. Farther south, in the Terai, the deposits are finer and less porous; the underground water rises or remains close to the surface, producing wet, marshy conditions. Option A correctly states both parts of the change. Option B is wrong because these foothill belts contain freshwater streams and groundwater, not only sea water. Option C is wrong because mangroves belong mainly to saline tidal coasts and corals are marine formations; neither describes the Bhabar–Terai transition. Option D is wrong because the Terai is notably wet and marshy, not a completely dry desert, and Bhabar is not one either. Exam cue: porous Bhabar makes streams disappear; wet Terai brings water near the surface.