B- is the answer
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Answer:
Chemical changes occur when a substance combines with another to form a new substance, called chemical synthesis or, alternatively, chemical decomposition into two or more different substances. These processes are called chemical reactions and, in general, are not reversible except by further chemical reactions. 
Explanation:
 
        
             
        
        
        
Answer:
Both require time, but velocity requires displacement and speed requires distance
Explanation:
For calculating speed we require time and distance because speed is defined as the distance per unit time and as speed is a scalar quantity it does not have any direction
But for calculating the velocity we require time as well as displacement because velocity is defined as the displacement per unit time and as velocity is a vector quantity it has direction
Displacement is the shortest distance between the initial position and the final position and it has a specified direction as well
 
        
                    
             
        
        
        
Many elements show very strong similarities to each other.<span>For example, lithium (Li), sodium (Na), and potassium (K) are all soft, very reactive metals. 
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Answer:
Fault-block mountain
Explanation:
I got it right on the assignment