The correct option is A.
The nature is organized in such a way that, one organism's waste is what the other organism will use as its own resources. For instance,  during the process of photosynthesis, the oxygen that is produced as the by product of the photosynthesis process is what humans use to carry out their own breathing process.
        
                    
             
        
        
        
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
 
        
             
        
        
        
those would be myofibrils
        
             
        
        
        
Answer:
1 in 4 people. 
Explanation:
Research studies results.