The two substances are rock (molten and solid) and metal (solid + liquid).
Layers of the earth from the outside in:
1. crust. hard rock/dirt/ground. Shell
2. mantle. melted rock and stuff. Egg white
3. core. Outer core - liquid. Inner core- solid. Nickle and iron. Yolk
 
        
             
        
        
        
i believe the answer is b radioactive nucleotide
 
        
                    
             
        
        
        
Answer:
ATP
Explanation:
ATP is an energy storing molecule which can help with active processes like active transport. It stands for Adenosine triphosphate