CARBON CYCLE 



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FIG. 142. The Carbon Cycle. Why is it necessary to eat food containing 

 carbon? Why is oxygen necessary? What is given off by expiration? 

 Why must plants have CO 2 ? What does the plant take from the soil? 

 What is produced from carbon dioxide and water in the plant? What is 

 left over after starch is manufactured? What becomes of the oxygen 

 which plants give off to the atmosphere? What is meant by the carbon 

 cycle? 



