REVIEW QUESTIONS 127 



come up they may be transplanted into tin cans filled 

 with good soil, and allowed to grow. There should be 

 openings in the bottom of the cans? Why? Make a 

 drawing of how each kind of tree starts from its seed. 



b. When the little trees are a few inches high they 

 may be taken home and olaced in the garden, unless they 

 are trees which cannot live in your climate. In this case 

 they must be kept in the house. 



Review Questions, 23. 



1. How can you show that plants need light? 



2. What is a flame? How can you prove your 

 answer? 



3. Do all crystals have the same shape? 



4. Name six of the harmful drinks. Do they always 

 show the harm which they are doing? 



5. What causes water to be hard? 



6. How do birds help the farmer? How do they 

 harm him? Which is greater, the help or the harm? 



7. What is the good of knowing the names of 

 flowers? 



8. Parks have been called the "breathing places" of 

 a city. Explain why this is a good name. 



9. If all the forests were burned or chopped down 

 what would be the effect upon the country? 



10. Name all the advantages of having forests. 



49. A Queer Plant Yeast. 



All the plants which we have studied, except bac- 

 teria, have been large enough to be seen. All of these 

 visible plants have needed light, heat, air, water and 



