1) In any ecosystem, the ultimate source of energy is the sun. 2) chlorophyll in plants absorb light energy which is converted during photosynthesis.

http://eo.ucar.edu/kids/green/cycles6.htm
The carbon process is made up of processes by which carbon dioxide is removed from and restored to the environment.

Removal of carbon dioxide from the environment

During photosynthesis , green plants absorb carbon dioxide from the atmosphere and use it to manufacture carbohydrates.

The glucose may be changed to other organic compound like amino acid.

The animals feed on green plants , the carbon compounds become part of these animals OR the carbon compounds may also be preserved in fossil fuels like coal

Release of carbon dioxide into environment

carbon dioxide is release into the environment through:
1) respiration
during respiration , carbon compounds are broken down into their bodies and carbon dioxide is released into environment.
2) COMBUSTION: when fossil fuels are burnt, the carbon compounds preserved in the fossil fuels are broken down and carbon dioxide is realeased
3) Decay: when organisms die, their bodies are broken down by decomposers , carbon dioxide is released and some simple substances are absorbed by decomposers and become part of their bodies . when decomposers respire , they too give out carbon dioxide .
The carbon cycle is vital as it provides us a continuous supply of carbon dioxide for plants and allows energy to flow through the ecosystem