किस नदी को अपने लगातार मार्ग परिवर्तन के कारण आने वाली विनाशकारी बाढ़ के कारण 'बिहार का शोक' कहा जाता है?

Which river is the largest tributary of the Ganga in terms of water discharge (volume of flow)?

The Luni river, which originates in the Pushkar valley of the Aravalli Range, terminates in which of the following?

The Indian drainage system is broadly divided into the Bay of Bengal drainage and the Arabian Sea drainage based on orientation to the sea. They are separated from each other along the major water divide running through which river basins?