Which process in the carbon cycle takes the longest to complete? a. formation of fossil fuels b. respiration in animals c. photosynthesis in plants d. emission of waste

ANSWER:- option A formation of fossil fuels.

Explanation:-

Fossil fuels are formed from dead and decaying plants and animal.When the dead and decaying plants and animals are exposed to heat and pressure over a long period of time they get converted to oil, coal, gas etc.These oil ,coal, gas are called as fossil fuels.The entire process of formation of fossil fuels can take place over a million of years.In contrast to the formation of fossil fuels , the process of photosynthesis in plants, respiration in animals and emission of waste is a phenomena which occurs at daily basis and over a short interval of time.

So, the formation of fossil fuels is the phenomena which takes the longest time in the carbon cycle.