Fill in the Blanks :
(1) The four oceans on earth are
(i). ………. (ii). ……… (iii). …….. (iv). ……..
(2) Gaddi, Bakarwal and Bhotlya tribes of Himalayas reside there in ……… season.
(3) ……….. is the area where river flows along with its tributaries.
(4) A stream of water flowing naturally on land is called as ……….