Duba wurin da ke ƙasa sannan ka amsa tambayar daga baya a cikin harshe ɗaya kamar yadda wurin yake:  Passage: Duniya ita ce kawai duniyar da aka sani da tekuna na ruwa mai ruwa a farfajiyarta, kodayake Mars yana da kankara da kuma irin wannan duniyar a wasu tsarin hasken rana na iya samun teku. Har yanzu ba a bayyana inda ruwan duniya ya fito ba, amma, idan aka gani daga sararin samaniya, duniyarmu tana kama da "blue marble" na siffofinta daban-daban: tekuna, kankara, girgije. Tekun duniya da ya kai cubic kilomita 1,335,000,000 yana ɗauke da kashi 97.2 cikin ɗari na ruwan da aka sani kuma ya rufe fiye da kashi 70 cikin ɗari na dukan duniya. Sauran kashi 2.15% na ruwan duniya ya daskare, wanda aka samo a cikin kankara da ke rufe Tekun Arctic, da kankara da ke rufe Antarctica da tekun da ke kusa da ita, da kuma kankara da yawa da kuma ajiyar ƙasa a duniya. Sauran (kimanin kashi 0.65% na duka) suna samar da matatun ruwa na karkashin kasa ko matakai daban-daban na zagayen ruwa, wanda ke dauke da ruwan zuma wanda yawancin rayuwar duniya ke fuskanta da amfani da shi: tururi a cikin iska, gajimare da yake yin sannu a hankali, ruwan sama da ke fadowa daga gare su, da tabkuna da koguna da aka kirkira kai tsaye yayin da ruwanta ke sake gudana zuwa teku. Mamayar teku a duniya ita ce marubucin Burtaniya Arthur C. Clarke ya taɓa lura cewa "Duniya" da an fi kiranta "Ocean". Nazarin kimiyya na ruwa da zagayen ruwa na Duniya shine ilimin ruwa; hydrodynamics yana nazarin kimiyyar ruwa a cikin motsi. Binciken kwanan nan game da teku musamman shi ne binciken teku. Wannan ya fara ne a matsayin nazarin siffar raƙuman ruwa na teku amma tun daga lokacin ya fadada zuwa babban filin da ke da yawa: yana nazarin kaddarorin ruwan teku; nazarin raƙuman ruwa, tides, da raƙuman ruwa; taswirar bakin teku da taswirar teku; da kuma nazarin rayuwar teku. Sashen da ke kula da motsi na teku, da dakarunta, da kuma dakarun da ke aiki a kan shi an san shi da ilimin kimiyyar teku. Ilimin kimiyyar halittu na ruwa (kwakwalwar halittu) yana nazarin tsire-tsire, dabbobi, da sauran kwayoyin da ke zaune a cikin yanayin yanayin teku. Dukansu suna da ilimin kimiyyar kimiyyar kimiyyar kimiyyar kimiyyar kimiyyar kimiyyar kimiyyar kimiyyar kimiyyar kimiyyar kimiyyar kimiyyar kimiyyar kimiyyar kimiyyar kimiyyar kimiyyar kimiyyar kimiyyar kimiyyar kimiyyar kimiyyar kimiyyar kimiyyar kimiyyar kimiyyar kimiyyar kimiyyar kimiyyar kimiyyar kimiyyar kimiyyar kimiyyar kimiyyar kimiyyar kimiyyar kimiyyar kimiyyar kimiyyar kimiyyar kimiyyar kimiyyar kimiyyar kimiyyar kimiyyar kimiyyar kimiyyar kimiyyar kimiyyar kimiyyar kimiyyar kimiyyar kimiyyar kimiyyar kimiyyar kimiyyar kimiyyar kimiyyar kimiyyar kimiyyar kimiyyar kimiyyar kimiyyar kimiyyar kimiyyar kimiyyar kimiyyar kimiyyar kimiya.  Tambaya: Yaya yawan ruwan da ke rufe duniya?
kashi 70 cikin dari