<span>Activation energy refers to the amount of energy required by certain chemicals for them to have a reaction. 
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its true............................................true
 
        
                    
             
        
        
        
The structure is calcium ions.
        
             
        
        
        
Progesterone is a steroid hormone that is usually made by the adrenal cortex along with the gonads, which consists of the ovaries and testes
hope this helps