Magnesium bromide= MgBr2
Potassium chloride= KCl
        
             
        
        
        
Answer:
True
Explanation:
A mole is defined as 6.02214076 × 1023 of some chemical unit, be it atoms, molecules, ions, or others. The mole is a convenient unit to use because of the great number of atoms, molecules, or others in any substance.
 
        
                    
             
        
        
        
Answer:
B
Explanation:
I hope it helps you good luck
 
        
             
        
        
        
Protostars are less dense than other stars.  
Explanation:
Protostars are very young ‘stars’ made from hydrogen clouds that are beginning to coalesce and collapse under their weight. The hydrogen has not even begun fusing. Therefore, they are mainly made of hydrogen which is the lightest element in the universe.
Stars, however, have begun fusing hydrogen to other heavier elements like helium, carbon, oxygen, and iron. The elements are much heavier than hydrogen making other stars much denser than protostars. 
Learn More:
For more on protostars vs stars check out;
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