They add nitrogen to the soul through their nodules ! 
 
        
             
        
        
        
The earth rotates from West to East or if you want another way of saying it, counter-clockwise. It rotates from West to the East because the earth's Western Hemisphere (West) rotates to the Eastern Hemisphere, (East).
P.S. I hope this helps you!!
 
        
                    
             
        
        
        
Synaptic cleft
- A gap between the neurons