Because in that way we keep thinking about them. How can you forget something when you're thinking about it?!
        
                    
             
        
        
        
Answer: b. one atom transfers an electron to another atom
          
Explanation:
An ionic bond is also called as the electrovalent bond. It is a type of linkage that is formed by the electrostatic attraction formed between ions of opposite charge in a chemical compound.
These bonds are formed when the valence electrons from one of the atom are transferred to the another atom.
 
        
             
        
        
        
Living things cannot live without eachother due to the food chain, if an animal loses it's food so will his predator and so on. Soon they will end up extinct, this is why it's important to take care of animals.
        
             
        
        
        
Mycoderma aceti uses acetic fermentation to produce ATP
C2H6O+O2-->CH3COOH+H2O
Saccharomyces cerevisae uses alcoholic fermentation to produce ATP
C6H12O6-->2C2H5OH+2CO2
 
        
             
        
        
        
Answer
C. Electron transport chain