Answer:
mouth and or nose
Explanation:
air enters the respiratory system through the nose and mouth and passes down the throat and through a voice box.
 
        
             
        
        
        
C, because DNA is the smallest one
        
                    
             
        
        
        
Answer:
Active genotype - environmental effects
Explanation:
There are primarily three types of co-relation between genotype and environment which are as follows –  
a)	Passive genotype –environment effect – This depicts the relationship between the genetic characteristics acquired by a child from his/her parents and the environment in which he/she is raised.  
b)	Reactive genotype –environment effect – This represents a relationship between genetically acquired behaviour from parents and the reaction corresponding to such behaviour.  
c)	Active genotype –environment effect – This represents a relationship between genetic tendency of an individual and the environment condition selected by an individual .
 
        
             
        
        
        
Answer:
Yes, the faster the organism breathes, the greater air exchange. The blood will increase & stimulate much faster.