来源：学历教育在线 2017-03-09 责任编辑:李老师评论
Task：The diagram below illustrates the carbon cycle in nature.
The flow chart shows how the cycle of carbon is formed in the nature completely.Overall,this process has 3 main parts,including carbon absorbing,transferring and releasing.
Firstly,under the exposure to sunlight,plants like green trees begin a process known as photosynthesis which absorbs CO2 from the air.After the death and decay of these plants,the organic carbon is then transferred underground.Similarly,the carbon accumulated in dead animals which feed on plants in life,such as sheep,is also deposited in soil.Being pressed and mingled in deep earth for a long term,a part of trapped carbon is converted into the form of fossil ｏｒ fossil fuels.
In terms of releasing carbon back,there are generally 3 ways.Organically,physical respiration from both plants and animals produces and exhales large amount of carbon as CO2 into atmosphere.Spontaneously,root respiration of plants also extracts fixed carbon from soil.Besides,man-made activities that burn fossil fuels like car running ｏｒ factory manufacturing make serious gas emissions of CO2 in air.
Finally,the entrance of CO2 into atmosphere activates this natural cycle which consists of sun,air,creatures,land and human activities.