Ma u baahan tahay qalabyada tuubooyinka koontada ee 60° tayada sare leh?Buug-yarahayagu waxa uu ka kooban yahay cabbirro iyo agab alaab-qeybiyeyaal kala duwan, oo ay ku jiraan birta, naxaasta.Ku habboon qalabaynta iyo codsiyada warshadaha ee leh UK iyo USA BSPP xirmooyinka tuubooyinka dunta.