They are homologous because they have similar structure regardless of purpose
        
                    
             
        
        
        
Answer:
A deep layer of connective tissue gives structural strength. 
Explanation:
 
        
                    
             
        
        
        
Answer:
The polarity of the phospholipid makes it ideal for a building block of cell membranes.
Explanation:
There is the tails which are hydrophobic (water fearing) and the heads which are hydrophilic (water loving). These properties of phospholipids allow the tails to go towards eachother and heads to face the water which maintains a solid structure allowing certain materials to pass through. 
 
        
                    
             
        
        
        
B because when air is fully saturated with water vapor it is called humidity