Answer:
D- Iron
~+lil more info!+~ 
Iron is the ultimate nuclear “ash,” from which no nuclear energy can be extracted.
 
        
             
        
        
        
Answer: A
Explanation:
i took biology and all that fun stuff with trophic levels
 
        
                    
             
        
        
        
Mitochondrion because it’s the powerhouse of the cell. 
 
        
             
        
        
        
Warm-blooded creatures, like mammals and birds, try to keep the inside of their bodies at a constant temperature. They do this by generating their own heat when they are in a cooler environment, and by cooling themselves when they are in a hotter environment. To generate heat, warm-blooded animals convert the food that they eat into energy. They have to eat a lot of food, compared with cold-blooded animals, to maintain a constant body temperature. Only a small amount of the food that a warm-blooded animal eats is converted into body mass. The rest is used to fuel a constant body temperature.