"Alveoli" <span>is where gas exchange takes place between the lungs and the blood.
Hope this helps!</span>
        
             
        
        
        
Independent Variable is what you change in an experiment. A Dependent Variable is what you’re trying to find out. Constants are what you keep that same. Control Group is the standards to which comparisons are made.
        
             
        
        
        
Selective pressures created by environmental factors can lead to success of <span>mutual individuals.  So it is D</span>
        
                    
             
        
        
        
The surviving R strain transformed into a living S strain.
        
             
        
        
        
An example of a complex trait is 
weight.
Complex trait or quantitative trait is a trait that doesn’t behave according to simple Mendelian inheritance laws. These traits show a continuous range of variation and are influenced by both environmental and genetic factors. It is often said that complex traits<span> are those that are influenced by more than one factor.</span>