Answer:
PLEASE MARK AS BRAINLIEST!!
Explanation:
In evolutionary theory, adaptation is the biological mechanism by which organisms adjust to new environments or to changes in their current environment. ... The idea of natural selection is that traits that can be passed down allow organisms to adapt to the environment better than other organisms of the same species.
 
        
                    
             
        
        
        
As you talk in animals 
nucleus/ plasma membrane / mitochondria
if you talk in plants 
nucleus / the cell / plastid / mitochondria
        
             
        
        
        
Answer:
returns to the left heart, completing the pulmonary cycle
Explanation:
 
        
                    
             
        
        
        
2 is B. Water freezes and 4 is the rock breaks.