The walls of xylem cells are lignified (strengthened with a substance called lignin ). This allows the xylem to withstand pressure changes as water moves through the plant.
The cell membrane is flexible because of the presence of oil like substances called phospholipids, which gives it a fluid nature. While as the cell walls are rigid because of the presence of the thick layers of the substances like cellulose in plants, chitin in fungi and peptidoglycon in bacteria.
        
             
        
        
        
Explanation:
Though cases of a dog being affected by poison ivy are rare, if you have a canine companion with sensitive skin, you should keep him away from the plant, just in case. “After being in an area with poison ivy or oak, you should wash your dog,” Nold suggests.
 
        
                    
             
        
        
        
Adenosine triphosphate (ATP)
        
                    
             
        
        
        
I think it is control group