Tani waxay markeeda hoos u dhigi doontaa heerka carbon dioxide ee jawiga, maadaama geeddi-socodka cimiladu ay u beddelaan gaaska kaarboon-dioxide-ka gaaska adag ee karbonaatka ah. 600 milyan oo sano ee soo socota laga bilaabo hadda, isku-darka kaarboon-dioxide-ka ayaa hoos u dhici doona heerka ugu hooseeya ee loo baahan yahay si loo joogteeyo C3 photosynthesis: qiyaastii 50 qaybood halkii milyan. Waqtigan xaadirka ah, geedaha iyo kaymaha qaabkooda hadda jira ma awoodi doonaan inay sii noolaadaan, geedaha ugu dambeeya ee nool waa geedaha cagaarka ah ee cagaarka ah. Si kastaba ha noqotee, C4 kaarboonku wuxuu sii socon karaa isku-darka aad u hooseeya, ilaa 10 qaybood halkii milyan. Sidaa darteed dhirta isticmaalaya C4 photosynthesis biosynthesis waxay awoodi karaan inay sii noolaadaan ugu yaraan 0.8 bilyan oo suurtagal ah ilaa 1.2 bilyan oo sano hadda, taas oo u oggolaan do
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