Northern Plains of India

1: (b) Three, 2: (a) 7 Lakh square kilometer, 3: (c) Three, 4: (d) Ghaggar and Tista, 5: (a) Indus, 6: (b) Bhabar, 7: (c) Bhangar, 8: (d) Khadar, 9: (a) Bhabar, 10: (b) Terai