Answer:
no they are always working especially when sleeping becuase the body isnt using excess energy
 
        
             
        
        
        
Answer:
A
Explanation:
A is adaptations, not natural selection 
 
        
             
        
        
        
Answer:
bbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbb
Explanation:bbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbb
 
        
             
        
        
        
Petroleum Products
Petroleum and its products are mainly composed of carbon polymers (chains), as the backbone, with different structural and functional groups. Plastic, for example, is made of polypropylene and polybutylene which is mainly made of carbon atoms, whose monomers are linked in a chain to form polymers that make up the products. 
Synthetic rubber on the other hand is made of copolymers of carbon and other addictives such as styrene. Synthetic fiber is made of nylon that is composed of a copolymer between carboxylic acid and amides.
        
             
        
        
        
Answer:
Which of the following is an advantage of an in vitro experiment?
Variables and environmental conditions are controlled.
Explanation:
An advantage of in-vitro experiment is that the variables and environmental conditions are controlled because in-vitro experiment is performed outside a living organism with the environment in control