The answer should be
 B Both anabolic and catabolic reactions took place in the seed and tree when it was young and growing and both continue now even though the tree reached a stable mass.
The trees should be capable to do both anabolic and catabolic reaction when it is seed or when it is already a big tree. Anabolic reaction happens when the plant making bigger molecule from many smaller molecule, such as in photosynthesis. Anabolic reaction could increase the mass of the plants or be used to make food. Catabolism reaction used to extract energy from the food.
 
        
                    
             
        
        
        
Calcium is a chemical element with symbol Ca and atomic number 20. Calcium is a soft gray Group 2 alkaline earth metal, fifth-most-abundant element by mass in the Earth's crust. The ion Ca2+ is also the fifth-most-abundant dissolved ion in seawater by both molarity and mass, after sodium, chloride, magnesium, and sulfate.[5] Free calcium metal is too reactive to occur in nature. Calcium is produced in supernova nucleosynthesis.
        
             
        
        
        
Flower because the others are a organ which make the plant live but the flower is more of a decorative thing to make the plant stand out