QUESTIONS 553 



the sea, which is the oldest and easiest highway, is essential 

 to the progress of a nation. 



QUESTIONS 



What do the rock layers show in regard to the history of life ? 



Give several reasons why the same kinds of plants and animals 

 are not found all over the earth. 



How has the glacial period affected plants and animals and 

 man's activities? 



What plants and animals do you know that are particularly 

 adapted to the conditions in which they live? . 



How does the life of the sea differ from that of the land? 



How has the distribution of animals been affected by geographical 

 conditions ? 



How have different physical features of the earth affected man's 

 life and history? 



