During the carboniferous period, which occurred approximately 360 to 300 million years ago, most of earth was covered in dense rainforests. these rainforests were sustained by a humid and tropical climate that lasted for most of the carboniferous period. at the end of the period, earth's climate became much colder and drier, leading to a wide-scale collapse of the rainforests and a significant loss of vegetation. how might the collapse of the carboniferous rainforests have affected earth's carbon cycle? a. over millions of years, the decaying vegetation would have been buried and its carbon turned into fossil fuels. b. over time, the decaying vegetation would have absorbed a large amount of carbon dioxide from the atmosphere. c. the total amount of carbon in the carbon cycle would have increased as the vegetation decayed. d. the loss of vegetation would have decreased the total amount of carbon in earth's carbon cycle.