256 ELEMENTARY SCIENCE 



produce seeds. You should understand that they all have 

 the same general problem of reproduction to solve. The 

 seed-plants are the most successful plants in the world, 

 and this is chiefly because the seed is the solution of the 

 great problem of spreading out and multiplying. 



QUESTIONS 



1. What are the simplest plants? 



2. Did the first plants live in water or on land? 



3. How do the simplest plants reproduce ? 



4. What is the sex process of reproduction? 



5. How do land-plants differ from water-plants ? 



6. What land-plants lived before there were any seed-plants? 



7. How are seeds produced ? 



