INTRODUCTION TO PLAXTS 199 



From another point of view, we find that the dif- 

 ferences between the food habits of plants and animals 

 is not in the substances which they require, but in the 

 way they secure them. Starch and sugar, for example, 

 form an important part of both plant and animal food. 

 The animal secures this starch from a plant or some 

 other source in which it is all ready to be used. The 

 plant, however, manufactures its own starch and sugar 

 out of very simple substances, water (H 2 0) and carbon 

 dioxide (C0 2 ). The parts of the plant in which the 

 starch is made are the leaves. 



Questions 



1. What are the principal plants used by man for 

 food? For clothing? For fuel? 



2. Explain other uses of plants to man in addition 

 to the uses for food, clothing, and fuel. 



3. May a knowledge of plants be of any value to 

 you apart from its value in making a living? 



4. Name the trees with which you are familiar. 



5. When do the leaves first appear on these trees? 



6. Name the wild flowers you have noticed. 



7. What is the largest plant which you have seen? 

 The smallest? 



8. What are the three things necessary to plant 

 life? Are they also necessary to your life? 



9. What is a cell? What are its parts? 



10. What is a tissue? Give examples. 



11. What is known about the composition of 

 protoplasm? State five properties of protoplasm. 



12. Explain fully the chief differences between plants 

 and animals. 



