Answer: B
Explanation:
Cells do not have to have complex interworking parts, they just have to do the job for the body. The answer is B.
 
        
             
        
        
        
The manipulated variable would be the moisture content.
        
             
        
        
        
Answer:
1a. Sewage is a liquid byproduct or waste that is carried through a system for treatment.
1b. Local wildlife and such would begin to die and dissipate and the rivers water, untreated would become unviable.
 
        
             
        
        
        
Answer:
D
Explanation:
Atoms and molecules are the smallest units of matter.