Answer:
im not suuuuureeeeeeeee but i think its a
 
        
             
        
        
        
Answer: d. assimilating the nitrogen into their own biomolecules.
Explanation: I just had this question for an assignment. 
Hope this helps!  :)
 
        
             
        
        
        
The main function of the Krebs cycle is to generate energy for the cell. The Krebs cycle is also known as the citric acid cycle and is part of cellular respiration. Cellular respiration is a series of chemical reactions that cells use to break up sugars into a form that the cell can use. Cell respiration requires oxygen to take place. Cellular respiration consists of four stages:1. the breaking down of glucose into molecules (glycolysis)2. the link reaction - this process forms a link between glycolysis and the Krebbs reaction3. Krebbs reaction 4. The electron transport chain 
        
                    
             
        
        
        
Glial cells. More specifically, it could be oligondenrocytes, astrocytes, ependymal cells, schwann cells, microglia, or satellite cells, because they are all types of Glial cells.