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 their energy to grow in 

 the open flask? 



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 com 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 corn. 



Materials. — Entire soaked corn grains and some cut lengthwise 

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



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

 light-colored area on one side. This marks the position 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 endosperm of the corn 

 grain. 



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



