(b) Volcanic eruptions
Volcanic eruption is naturally occurring event. In Volcanic eruptions many toxic gases are released into the atmosphere such as carbondioxide, carbonmonoxide, hydrogen sulfide, hydrochloric acid and Sulphur dioxide etc. These toxic gases goes to the atmosphere and combine with water vapours forming the water acidic. When this acidic water comes to the earth surface, skin and valuable stones are damaged from it.
Fossil fuels, forest fires, and respiration and major metabolic process photosynthesis are left out of the model.
Explanation:The carbon cycle model contains all the activities but some points are missing in it. Oceans, the burning of fossil fuels should be explained. Natural elements such as coal and natural gas are the main elements of the carbon cycle.Because they are important compounds of the carbon cycle. The process of photosynthesis is very important in the carbon cycle. The process of volcanic eruption should be explained in the carbon cycle.