If Carbon Dioxide (CO₂)was Much More Abundant in Earth's Early

Multiple Choice

If carbon dioxide (CO₂) was much more abundant in Earth's early atmosphere,what happened to most of this gas?

A) It was dissociated by lightning into its components,carbon and oxygen,which then escaped from Earth's gravity.
B) It escaped into space because of its low molecular weight.
C) It combined with other substances to produce carbonate rocks in limestone.
D) It was dissociated by the ultraviolet radiation in sunlight,the carbon settling onto Earth while the oxygen remained in the atmosphere to support life.