10 THE SOIL AND ITS ORIGIN 



QUESTIONS 



1. What is soil and when was it formed? 



2. Name two classes of materials composing soil. 



3. Distinguish between them. 



4. What is meant by rock weathering? 



5. Name some of the forces which break up and cause rocks to decay. 



6. In what ways do plants and animals aid in the weathering of rocks? 



7. Is soU formation a simple process? Explain. 



8. When does weathering cease? 



9. What is the importance of "soil weathering"? 



10. Is it possible to observe the stages in the changing of rock into soil? 



11. What are the facts to be observed? 



12. In every case is soil formed from the rock found underlying it? Explain. 



13. Why should there be many different kinds and types of soil? 



14. What kinds have you seen? 



15. For an outhne summary of this chapter see table of contents. 



