PROBLEM 45 67 



Conclusion. — 1. How do you account for the presence of 

 carbon dioxide in the closed flask? 



2. Why did the seeds in the open flask grow? 



3. From what source did the seeds get theii- energy to grow in 

 the open flasl;: ? 



General Conclusion. — Write up a brief statement, using proof 

 to show that energy is locked up in food and that it can be released 

 and used only by oxidation. 



Problem 43 : To study the fruit of the corn plant. 



Materials. — Ripe corn on the cob. 



Method. — Compare the ripe corn on the cob with the picture 

 on page 67 of your Civic Biology and with specimens shown by 

 the teacher. 



Observations. — What differences are there between the young 

 and the old specimens? 



Conclusion. — Is the ear of corn a single fruit or a bunch of 

 fruits? Give reasons for your answer. 



Problem 44: To study the structure of a grain of com. 



Materials. — Entire soaked corn grains and some cut lengthwise 

 at right angles to the flat surface. Figure page 66, Ciiic Biology. 



Method and Observations. — In an entire corn grain find a 

 light-colored area on one side. This marks the posit ioii of the 

 embryo. 



In a grain cut lengthwise at right angles to the flat side find the 

 embryo. Describe its shape, position, and relative size compared 

 with the rest of the corn grain. 



Note. — The area outside of the embryo is known as the endosperm. 



Place iodine on the surface of the cut corn grain. Describe 

 what happens. Test for protein. 



Conclusion. — 1. What nutrients are present in the corn? 

 2. Where are they found ? 



Problem 45: To find the use of the cndospevnt of flic corn 

 grain. 



Materials. — Sprouted corn grains, scalpel, and sawdust. 



