Explanation:
If water did not expand when freezing, then it would be denser than liquid water when it froze; therefore it would sink and fill lakes or the ocean from bottom to top. Once the oceans filled with ice, life there would not be possible.
 
        
             
        
        
        
Answer:
spinal cord
Explanation:
Reflex actions are the involuntary action of the body in response to a signal or stimulus. The reflex action of body is controlled by spinal cord. 
Reflex arc acts as a neural pathways that transmit impulse to the brain via spinal cord. Sensory neurons pass through synapse in the spinal cord which activate spinal motor neuron to act immediately without any delay.
Immediate taking off hand from hot oven is an example of reflex action, which is regulated by spinal cord.  
Hence, the correct option is spinal cord.
  
 
        
                    
             
        
        
        
I believe its large blue vessel also known as vena cava
        
             
        
        
        
The hypothalamus sends signals to the pituary glands. The hypothalamus releases dopamine, so I think dopamine is a good answer?