Answer:
The correct answer is A. 3O₂ + 2Al → 2AlO₃ 
Law of conservation of mass states that mass can nether be created nor destroyed in a closed system or chemical reaction i.e. the total mass of the matter always remains the same throughout the chemical or physical change.
For example, in the given reaction 3O₂ + 2Al → 2AlO₃ the total mass of the reactants is equal to the total mass of the product. 
Mass of oxygen = 16 x 3 = 48 AMU
Mass of aluminium = 2 x 27 = 54 AMU
Total molecular mass of the reactants = 102 AMU
Total molecular mass of the product = 2 x 27 + 6 x 8 = 102 AMU.
Hence, the total mass of the matter remains the same.
 
        
             
        
        
        
For you to understand the process we can say that the weak will die. If the animal or organism can't get food or find any it is naturally "selected" to die.So a Cuticle could have evolved like that. Hope tgis is useful 
        
             
        
        
        
The answer would be D.nucleus, prokaryotic cells don’t have a nucleus instead their dna floats around inside the cell
        
                    
             
        
        
        
Answer:
2
Explanation:
Prokaryotic cells don't have a nucleus or membrane bound organelles
 
        
             
        
        
        
Answer:
dark blue: denser oceanic crust is subducting...
Explanation: