Answer:
Purposes that work to maintain homeostasis include the regulation of temperature, maintaining healthy blood pressure, maintaining calcium levels, regulating water levels, defending against viruses and bacteria.
Explanation:
 
        
             
        
        
        
Answer:
B replication
Explanation:
the teacher demonstrated, so the students were told to CARRY OUT THE *same* experiment, AKA REPLICATION  >:3
 
        
                    
             
        
        
        
Answer: double helix 
Explanation: The double helix of DNA is, like its name implies, in the shape of a helix which is essentially a three dimensional spiral. The double comes from the fact that the helix is made of two long strands of DNA that are intertwined—sort of like a twisted ladder.