I think 4. Because it’s really anywhere when you want. I think. If not 4 then 2 but I’m pretty sure it’s 4. Sorry if it’s wrong
        
             
        
        
        
Nouns since they dont express something instead describe
        
                    
             
        
        
        
<span>C. the bus broke down, so we had to walk.</span>
        
             
        
        
        
It's an informative piece, one to tell the reader about facts and not your opinions <span />
        
             
        
        
        
Answer:
Pavlov's Dogs and Discovery of Classical Conditioning. Pavlov's dog experiments played a critical role in the discovery of one of the most important concepts in psychology. While it was originally discovered quite by accident, these famous experiments led to the discovery of classical conditioning.
Explanation: