t6o The Great World's Farm 



left quite bare of covering, and yet even here plants man- 

 age to survive, some without any protection whatever, 

 others because they are buried under a deep layer of dead 

 leaves and stems. Whether in ** deserts" of ice or ''des- 

 erts" of sand, it would be equally difficult to find any 

 spaces of large extent where vegetable life of some kind 

 or other does not exist, at least during certain seasons of 

 the year. 



QUESTIONS FOR REVIEW 



1. How important is climate in the life of a plant? 



2. How do conditions vary in the same latitude? 



3. What is the great characteristic of the climate of the 

 equator. 



4. Show how the temperature of air and soil affect each 

 other in different latitudes. 



5. What effect has the presence or absence of moisture? 

 Illustrate. 



6. What influence has the gulf stream? 



7. Why are plants affected by the color of the soils in which 

 they grow? Illustrate. 



8. How do soils differ in the way in which they retain heat? 



9. Why is the equatorial climate not best for all plants? 

 Illustrate. 



10. Compare the conditions of plants in Nubia and in the 

 Far North. 



