Carbohydrates are digested in your mouth, stomach and small intestine. Carbohydrase enzymes break down starch into sugars. The saliva in your mouth contains amylase<span>, which is a starch digesting enzyme.</span>
        
                    
             
        
        
        
Answer:
The nitrogenous bases guanine and adenine are A. purines.
Explanation:
Adenine and guanine are purines, whereas the other two bases in DNA (thymine and cytosine) are pyrimidines.  The main difference between purines and pyrimidines is the number of rings that the base has: purines have two rings while pyrimidines only have one ring.  
In addition, phosphate group and sugar group cannot be the answer to this question because these two elements in addition to a nitrogenous base makes up a nucleotide.
Hope this helps!
 
        
             
        
        
        
Answer:
Two elements
Explanation:
Nitrogen and Oxygen only, (NO)
 
        
             
        
        
        
Answer:
DIFFUSION 
Explanation:
Water, carbon dioxide, and oxygen are among the few simple molecules that can cross the cell membrane by diffusion (or a type of diffusion known as osmosis ). Diffusion is one principle method of movement of substances within cells, as well as the method for essential small molecules to cross the cell membrane.