256 LIVING THINGS IN THEIR ENVIRONMENT 



" being alive" is. Our dog or cat exhibits his liveness in 

 running to meet us, in frisking about, in barking or mew- 

 ing, in eating and sleeping, and in any one of the various 

 things that a live dog or kitten will do. 



We can say what living things will do and predict pretty 

 well what they will do under certain conditions. We 

 know our dog will come to us when we call him, will growl 

 or bite when annoyed, will eat when hungry, and drink 

 when thirsty. He will retreat to his kennel to get out of 

 the sun and will whine to get in the house when he is cold. 

 And if we compare a boy or girl with a dog, we find them 

 very much alike in the way they act under similar con- 

 ditions. These conditions which, in the case of the dog, 

 the boy, or the girl, affect the organs of sight, hearing, 

 taste, touch, or some other sense, are called stimuli and 

 they all are said to react to stimuli of its environment. 

 Living things react to stimuli and things that are not 

 alive do not. 



SELF-TESTING EXERCISE 



Select from the following list those words that best fill the blank spaces 

 in the sentences below and arrange the words in proper numerical 

 order. A word may be used more than once. 



divisors dividing food characteristic 



factors substance creations animals 



plants , living kind environment 



life drink subtracting parts 



same responsive dead different 



stimuli inside turn multiplying 



middle outside respond similar 



cells other grow adding 



Living things differ from nonliving things in several definite 



ways. Living things always come from (1) similar (2) 



Reproduction is a (3) of both (4) and (5) Then 



living things (6) , not from the (7) like a crystal, but 



from the (8) Living things are always made up of tiny 



