<span>B) The speed is constant and velocity is changing. </span>
        
                    
             
        
        
        
Many theories can never be proven.  
Here are a few examples:
-- The moon orbits the Earth.
-- Gravity pulls all masses toward each other.
-- The Earth orbits the sun.
-- Everything is made of atoms and molecules.
-- Atoms are made of protons, neutrons, and electrons.
-- Electrons moving through a wire make electric current.
-- The center of the Earth is molten iron and nickel.
-- The source of the sun's energy is nuclear fusion in its core.
-- Almost all galaxies are moving away from us.
-- The universe is expanding.
None of these statements can be proven.  That's why they're not called 
Facts or Laws.  
It also tells you that some pretty powerful stuff has been done with concepts 
that can't be proven.  If you want to make an idea look foolish, that doesn't 
happen when you say "it's only a theory".
        
                    
             
        
        
        
All of them is correct. Answer E
        
             
        
        
        
<span>Of these choices, neuronal communication between the brain and the muscles of the leg is best conceptualized as electrical and chemical signaling.
The brain sends signals of the electrical and chemical type to reach the leg and move its muscles. Once these signals get to the muscles of the leg, they are moved into motion as a result of the brain "ordering" the leg to move so that a person could get up or get to another place.
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C) Hydrogen of water is separated from oxygen. DOES NOT OCCUR!