Waa maxay waxyaabaha ugu muhiimsan ee laga helo dhulka?
Context:Dhulka culeyskiisu waa qiyaastii 5.97×1024 kg (5,970 Yg). Waxay badanaa ka kooban tahay birta (32.1% miisaan ahaan), oksijiin (30.1%), silikoon (15.1%), magnesium (13.9%), baaruud (2.9%), nikkel (1.8%), kalsiyum (1.5%), iyo aluminium (1.4%), iyadoo 1.2% ee soo hartay ay ka kooban yihiin tiro yar oo walxo kale ah. Sababtoo ah kala soocida culeyska, nuxurka waxaa ugu horreyn ka kooban walxaha cufan: birta (88.8%), oo leh qadar yar oo nikkel ah (5.8%), baaruud (4.5%), iyo wax ka yar 1% walxaha raadadka ah. Waxyaabaha ugu badan ee dhagaxyada ku jira dhulka waa oksaydhada. In ka badan 99% dhulka waxaa ka kooban oksaydyo kala duwan
Dhulku wuxuu ka kooban yahay bir, oksijiin, Silicon, Magnesium, sulfur, nickel, calcium iyo aluminium.