Nitrogen is not necessary <span />
        
                    
             
        
        
        
You need to read the introduction like this
        
             
        
        
        
Answer:
Grass 
Explanation:
Grass can make its own food by using chlorophyll to turn sunlight into the energy that it needs to function.
 
        
                    
             
        
        
        
Clostridium, Bacteroides, and the methane-producing archaea (methanogens), are called obligate anaerobes because their energy-generating metabolic processes are not coupled with the consumption of oxygen.
        
             
        
        
        
Answer: heres the 3 main functions.
Explanation:
membranes have three primary functions 1) they keep toxic substances out of the cell 2) they contain receptors and channels that allow specific molecules, such as ions, nutrients, wastes, and metabolic products, that mediate cellular and extracellular activities to pass between organelles and between the cell and the outside environment and 3) they separate vital but incompatible metabolic processes conducted within organelles.