Answer:
The best example of hypothesis which leads to new experiment methods was done by Morgan where he used fruit flies.
 
        
                    
             
        
        
        
A unicellular or single celled organism is the term for organisms composed of only one cell.
I hope this helped!
 
        
                    
             
        
        
        
Yes an atom is a substance.
 
        
                    
             
        
        
        
Substrate-Level Phosphorylation is a mode of ATP synthesis that occurs when an enzyme transfers a phosphate group from a substrate molecule to ADP. 
This is from my AP Bio notes. Not 100% sure, but it does sound the closest in comparison to other processes.