FUNCTIONS OF LIVING THINGS 



45 



which are woody tubes in plants and blood vessels in animals. 

 Then this digested food must finally become part of the living 

 organism by assimilation. 



Excretion. Wastes, such as water, carbon dioxide, and urea, are 

 formed in the body by oxidation and other changes. If these wastes 

 are not eliminated at once, they interfere with the normal working 

 of the body. Therefore excretion is a necessary body function. 



Reproduction. Reproduction, or the formation of new organisms, 

 is the outcome of all the nutritive processes. Plants and animals 

 have various methods of giving rise to new plants and animals. 

 But the result is the same in both cases ; that mysterious something 

 we call life is started again as a seed, an egg, or a baby animal to 

 become in time a parent of another generation of life. Some of 

 the material in the following units deal with this life function. 



Practical Exercise. List for comparison the evidences of life processes (men- 

 tioned in preceding paragraphs) in a common plant and in an animal. 



1 ■ *• . '- 





Or '^^^^ 



§;\ %' 







H. Armstrong Roberts 

 Animals and plants give rise to new organisms. These offspring resemble their parents and 

 each other. Yet, very seldom do we find two individuals exactly alike. 



Self-Testing Exercise 



.Living things, because they are (1) of (2) are called 



organisms. Both plants and animals have similar (3). 



