Answer:
Energetic coupling of chemical processes in metabolic pathways Biochemical systems couple energetically unfavorable reactions with energetically favorable reactions. These reactions can be part of catabolic pathways where complex substances are broken into simpler ones with the release of energy or anabolic pathways where complex molecules are synthesized with an input of energy.
Explanation:
 
        
             
        
        
        
<em>by definition- a stem cell is an undifferentiated cell of a multi-cellular organism which is capable of giving rise to indefinitely more cells of the same type, and from which certain other kinds of cell arise by differentiation.</em>
an example
Stem cells have the potential to be whatever they want to be. Stem cells are able to develop into many different types of cells and can repair your body. 
there are two types
adult stem cells and embryonic stem cells
 
        
             
        
        
        
Answer:
The inner membrane of the mitochondria can be compared functionally to the
thylakoid membranes of the chloroplast because both contain a system for:
electron transport.
 
        
             
        
        
        
Answer:
Darker patches in the skin. Not mater the size, the small patch could be hiding cancer with the possibility of tumors under the patch of skin.
 
        
                    
             
        
        
        
Explanation:
The organ can become more and more weak, until it is unable to effectively send blood around the body. The blood tends to back-up in the body and fluid passes into the tissues, this leads to swelling. This congestion is the reason heart failure is often called congestive cardiac failure