Answer:   Determined by genetic and environmental factors. 
Explanation:
Are determined by genetic and environmental factors and the interaction of such factors, but not with absolute certainty. This development system model includes both influences of species typical genes and the influences of a species typical rearing environment.   Relatively rapid increase in obesity, the change stems from changes in the environmental context. 
 
        
             
        
        
        
Spinal cord is the part of the central nervous system which is used to serve as  the main communication link between the body and brain
        
                    
             
        
        
        
I only know this so far-
4 elements 
Nitrogen (N)
Hydrogen (H)
Sulfur (S)
Oxygen (O)
        
                    
             
        
        
        
Answer:
b. quantitative observation 
if its wrong sorry.
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