The fill in the blank answer is increased
        
             
        
        
        
I believe it is E. Could be wrong though.<span />
        
                    
             
        
        
        
Adenine, Thymine, Cytosine & Guanine
        
             
        
        
        
Answer: An Organ System
Explanation: Vascular plants have two distinct organ systems: a shoot system, and a root system. The shoot system generally grows above ground, where it absorbs the light needed for photosynthesis. The root system, which supports the plants and absorbs water and minerals, is usually underground.
 
        
             
        
        
        
B - Hydrogen Bond
A and D are incorrect as these are bonds either between metals and nonmetals or non metals and non metals. C is incorrect as this term is a joining of sugar molecules.
Hope this helps!