Answer:
The electron density of a polar bond accumulates towards one end of the bond, causing that end to carry a slight negative charge and the other end a slight positive charge. Likewise molecules in which there is an accumulation of electron density at one end of the molecule, giving that end a partial negative charge and the other a partial positive charge, are called polar molecules.
 
        
                    
             
        
        
        
Answer:
One
Explanation:
Sodium (Na) has one valence electron so it gets one dot.
 
        
             
        
        
        
Answer:
They are used to transport electron during metabolic reaction. 
 
        
             
        
        
        
Answer:
False
Explanation:
An aquifer is an underground layer of water-bearing permeable rock or rock fractures or. The system shows two aquifers with one aquitard. Some abundant small openings store a large quantity of water. Groundwater may exist in underground rivers or underground cave systems where water flows freely underground. If the impermeable area overlies the aquifer, pressure could cause it to become a confined aquifer.