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TEXTBOOK OF ZOOLOGY 



Chiorophyll 

 Sunlight 



\nt(zrmedigte 

 decomposition 

 products 



\ 



Bacteriai 

 decomposition 



/ formoldehyde 



Living ^/Carbohydrates , 

 animals \ fats (and proteins) 



/ 



Respiration 

 K ^ 



Dead 

 organisms 



Pig. 3._The carbon cycle and the fundamental living process. 



Inyalra -^rnn fO-) 



Hrnnnir- food 



a AnimQ/ 



Sl l /~^trf i-.t of Oa 



Fig. 4.— The metabolic processes of plants and animals ^s well as the food 

 manufacturing process (photosynthesis). (Redrawn by permission f i om Wolcott, 

 Animal Biology, published by McGraw-Hill Book Company, Inc.) 



