Answer;
-On the polar end or the hydrophillic end of the protein. 
Explanation; 
-Each amino acid has at least one amine and one acid functional group as the name implies. The different properties result from variations in the structures of different R groups.The R group is often referred to as the amino acid side chain. 
-Side chains which have various functional groups such as acids, amides, alcohols, and Amines will impart a more polar character to the amino acid. Polar amino acids include serine, threonine, asparagine, glutamine, histidine and tyrosine.
Therefore; serine being a polar or hydrophillic  amino acid will be found on the polar side chain of the protein.
 
        
                    
             
        
        
        
Answer:
Transmission electron Microscope 
Explanation:
It produces thin slices of photography and extremely tiny things. The disadvantages are that its expensive, and you cannot test living things with it, its also massive 
 
        
             
        
        
        
Answer:
Negative feedback.
Explanation:
The production of erythropoietin by the liver and kidneys is a negative feedback because with the production of erythropoietin, our body tends to move to become more stable state. The erythropoietin is produced by the liver and kidneys to increase the production of red blood cells if the quantity of red blood cells are lower than the normal range. If the number of red blood cells are decreases the oxygen level in our body is low that leads to unstable condition of the body but when the concentration of red blood cells increases, the body move towards stability.