गण्डक नदी का उद्गम स्थल कहां है ? - Where is the origin of the Gandak River? - Gandak Nadi Ka Udgam Sthal Kahan Hai ? UP GK in hindi, अपवाह तंत्र,झीले, सिंचाई एवं भूगर्भ जल Utar Pradesh question answers in hindi pdf Nepal questions in hindi, Know About UttaraKhand UP GK online test UP GK notes in hindi quiz book Bihar