The correct answer is "neurons".
Neurons are nerve cells which connect to each other using synapses and form neural networks. They exhibit high levels of specialization and are the primary components of the central nervous system. 
Myofibrils are contractile fibers which form the striated muscle cells. Sarcomeres are the structural unit of the myofibrils. 
        
             
        
        
        
It is harmful because motor vehicles spit out gas and like fumes. That can lead to pollution in the air.
It is beneficial because it helps people get to places they need to get to quicker
        
             
        
        
        
That would be yes cause thy are all the same cells unless in in different envirment 
        
                    
             
        
        
        
Do you mean ion pumps in the membrane of cell?
If so, then ion pumps maintain an electrochemical gradient across the membrane. 
        
             
        
        
        
Answer:
Molecules stop moving at freezing point. Helium has the lowest boiling point. The molecules move very quickly at boiling point.
Explanation:
Heating up- molecules move faster. Cooling down- molecules move slower