PRUBLE.M HI 



129 



How does it get to the plant? D()(\s the plant use oxyj^eii as the 

 animal does? 



Conclusion. — 1. How are plants able to store up ener^;y? 

 Where does it come from? What becomes of it? 



2. Explain the carbon cycle. 



3. Explain the oxygen cycle. 



idd etc 



.Animal Life 

 )ecompQsing Bacteria 



Problem 110 : To find out tlie course of nitrogen in i/s rela- 

 tion to plants and animals. 



Method. — Begin at the point of the diagram marked " Free 

 N/' following the direction of the arrows. 



Observations. — What 

 do we mean by '' free 

 nitrogen"? Where is it 

 found? How do green 

 plants get the free nitro- 

 gen? In what form does 

 the nitrogen get into the 

 animal body? In what 

 form does the nitrogen 

 leave the bodies of ani- 

 mals? What causes this material and the dead bodies of animals 

 to become usable by plants? Does any nitrogen get back into 

 the atmosphere again? If so, how and when? Look this up in 

 any good book of reference. 



Conclusion. — 1. Fill out a summarizing table like the accom- 

 panying. 



2. In your notebook 

 exj)lain in a well-writ- 

 ten jiaragraph what is 

 meant bv tlie nitrogiMi 

 cycle. 



y^/ti^ Nitrites 



«/j5 ates-* — Nitric Bacteria 



l>laivts 



Gre.e.*v 



Ixvc OTixe of 

 A.nirr»als /rom 



Bacteria 



Owtgo oj 



AlA I IIX C\\ fi to 



rrohlem 111: To prove a hay infusion is an unbalanced 

 aquarium. 



Materials. — Hay, glass jar, microscope, glass slides, cover 

 glasses, and pipette. 



HUNTEK LAB. PUGB. 9 



