How would the carbon cycle be affected if no bacteria were present?

Without decomposers, the carbon would remain locked in dead organisms and could only be released through combustion. However, humans are having a huge impact on the carbon cycle by the combustion of buried fossil fuels, which is increasing carbon in the atmosphere rapidly.

he forelimbs below belong to four species that descended in a direct line from the ancestral mammal shown above. of the four descendants shown, which species most likely appeared earliest in evolutionary history?