Answer: solid
Explanation: i remember learning this but if im wrong im sorry
 
        
                    
             
        
        
        
Answer: The sunflower is intolerant to shade exposure and needs full sun exposure. It has adapted to this necessity by having a heliotrope class head which roared to follow the sun, hence the name sunflower. The heads of the sunflower are heliotropic, meaning movement of the head redefine to the direction of the sun. 
You can find more out on the website http://bioweb.uwlax.edu