260 



ELEMENTARY SCIENCE 



Neither liverworts nor mosses have flowers or seeds, but 

 they made great progress in learning to live on land. 

 The danger to plants in living on land was that they would 

 be dried out and killed by exposure to air. If a fish is 

 taken out of water and left in the air, it cannot continue 

 to live. And so certain Algae gradually learned how to 



FIG. loo. Ferns. 



protect themselves from drying out. And when they 

 learned, they were no longer Algae, but became liverworts. 



This second group of plants, therefore, took a great step 

 in advance, and deserve to live in the second story. They 

 made it possible for plants to begin to occupy the land 

 surface. 



3. The First Woody Plants. These plants occupy the 

 third story of our apartment-building. The most common 



