TABLE OF CONTENTS 



IX 



PROBLEM 



III. What Are Some Useful Things That Bacteria Do? 



IV. What Are Yeasts and What Do They Do? 

 V. To Learn about Some Destructive Fungi . 



VI. What Are Molds? What Do They Do? . 



VII. What Are Some Examples op Common Algae? 



VIII. What Is the Life History of a Moss Plant? 



IX. What Is the Life History of a Fern Plant? 



X. What Are Some Examples of Spermatophytes? 



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I. 

 II. 



III. 



IV. 



V. 



VI. 



VII. 



VIII. 



IX. 



X. 



XI. 



UNIT VIII. HOW DO WE CLASSIFY THE ANIMALS? 



What Are the Characteristics of One-celled Animals? 

 What Are the Characteristics of Some Simpler Inverte- 



brates 



What Are the Characteristics of the Arthropods? 

 What Are the Characteristics of the Mollusks? 

 What Are the Characteristics of the Fishes? . 

 What Are the Characteristics of Amphibians? 

 What Are Characteristics of the Reptiles? 

 What Are the Characteristics of Birds? . 

 What Are the Characteristics of Mammals? 

 What Story Is Told by the Fossils? . 

 What Is Man's Place in Nature? 



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UNIT IX. WHAT EFFECTS HAVE THE SURROUND- 

 INGS ON THE LIVES OF PLANTS AND ANIMALS? 



I. What General Biological Relations Exist between 



Plants and Animals? 282 



II. What Do We Mean by the Nitrogen, Oxygen, and 



Carbon Cycles in Nature? 285 



III. What Is Symbiosis and How Does It Differ from 



Parasitism? 287 



IV. How Does Man Disturb the Balance of Nature? . . 289 



V. How Do the Factors of the Environment Affect 



Ecological Relationships? 290 



VI. Why Do Plants and Animals Form Communities? . . 298 



VII. What Is an Ecological Succession? 300 



VIII. What Do We Mean by Geographic Distribution of 



Living Things? 305 



