Coral limestone are examples of rocks whose formation is not explained by the rock cycle. Corals are tiny marine organisms that absorb carbon dioxide dissolved in sea water and use this to secrete hard skeletons of calcium carbonate. These organisms can build massive reef structures over the course of thousands of years.
The answer is A to this question primary
Because Cyanobacteria appeared
Cyanobacteria's excrement formed a lot of oxygen in the atmosphere which make the earth temperature cold
This allow a liquid water to formed on the surface ( because if the temperature is too high, the water will evaporate) and eventually formed oceans
Answer: The answer is A
Explanation: I took a test with this question and I got it correct.