blood flows at a high pressure, so if the arteries are thin and less muscular, the arteries can explode due to the pressure. so it needs thick and muscular properties so that it can withstand the increasing pressure of the flow of blood.
im not sure why it needs to be elastic. Hope it helped :)
 
        
                    
             
        
        
        
<span>i think Comparative morphology
i could be wrong tho</span>
        
                    
             
        
        
        
hi I just need brainliest answer 
I think good insulator
 
        
             
        
        
        
Well those that are in that ecostems could died from no water or the could walk on it and it breaks