288 FIRST YEAR COURSE IN GENERAL SCIENCE 



by day, and throughout all seasons; so in the sunshine it 

 stores energy for future need. 



EXERCISES 



1. What is the reason that the petals of a flower are generally 

 showy? 



2. Of what use to a flower is its odor? 



3. What two parts of the flower do you consider most important? 

 Why? 



4. Why do not snowdrops and lilies of the valley open and close 

 their flowers as tulips do? 



6. (a) How could you show that starch was present in the seed- 

 leaves of an embryo? (b) For what purpose is food stored in a seed? 



6. (a) How is sensitiveness to the stimulus of contact of use to 

 a nasturtium? (6) To a grape vine? 



7. The beet and the turnip are two of the plants that do not blos- 

 som until the second summer after a seed is planted. What relation 

 is there between this fact and the fact that they have thick roots? 



8. Explain how a plant can grow and blossom from a bulb put 

 into water only. 



9. What does a plant gain by its response to the influence of light? 



10. Of what advantage to a plant is the folding of its leaves at night? 



11. Name all the steps in tracing man's energy back to the heat of 

 the sun. 



