I think tracheae which is B not sure tho
        
                    
             
        
        
        
<span>The part of the ear where sound wave compressions and
rarefactions cause the eardrum to vibrate is the middle ear. The 8th
nerve in the inner ear actually converts the mechanical energy to electrical
energy for transmitting to the brain. A membrane called the tympanic membrane
separates the middle ear from the outer ear. Whenever a sound reaches the ear,
it creates a sound wave that creates vibration in the eardrum. The pressure
when high pushes the membrane inwards while low pressure sound waves helps the
eardrum to come outwards.  </span>
        
             
        
        
        
Water is capable of dissolving a variety of different substances, which is why it is such a good solvent. And, water is called the "universal solvent" because it dissolves more substances than any other liquid. This is important to every living thing on earth. 
I hope that’s help:)
        
                    
             
        
        
        
 I believe the correct answer will be A
        
             
        
        
        
<span>A.) high-energy 3-carbon molecules...
     
Like 3-Phosphoglyceric acid is a 3-carbon sugar which completes the cycle by converting itself into 6-carbon molecule.
Hope this helps!
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