Answer:
d) beaks and claws
Explanation:
Birds have many physical attributes that help them fly in the air. They include a lightweight body, streamlined boat shaped body, and wings made of feather to flap through the air.
Though birds' beaks and claws are important factors for survival and catching prey, they are not necessarily the factors which help them fly. However, beaks are considered aerodynamic and hydrodynamic because most of them are coned shaped. 
So option D is the correct answer. 
 
        
             
        
        
        
Good morning 
Tell me if this is mean sorry but it is evening
        
                    
             
        
        
        
Bet let set tell me if you met something else
        
                    
             
        
        
        
Furthermore. It is used to add onto something that has been already said.