Wood isn't as tough as rock. Wood also breaks down in weather and cracks under pressure. Plus rocks were more accessible.
        
                    
             
        
        
        
The wave length becomes shorter and the pitch becomes higher
        
                    
             
        
        
        
Answer:
The 'little brain' attached to the rear of the brainstem is called the cerebellum. See the explanation below, please.
Explanation:
The cerebellum is in the back of the brain, it is small in size. It is responsible for functions such as integrations of sensory and motor pathways, balance, coordination of movements, posture.
 
        
                    
             
        
        
        
The meat in the freezer is frozen.  
Everything else in the freezer is frozen too.  
Nothing in the refrigerator is frozen.  
The freezer is colder than the refrigerator.  <span>
Mildred takes a pound of frozen hamburger meat out of the freezer 
and puts it into the refrigerator.  The meat is colder than anything
else that's in there.
Heat flows from the air in the refrigerator into the frozen hamburger (C)
and warms up the meat.  When the temperature of the meat warms up
to the temperature of the air in the refrigerator, the heat stops flowing.</span>