Answer:
A. Archaea / Bacteria
Explanation:
Bacteriorhodopsin is a protein used by Archaea, most notably by halobacteria, a class of the Euryarchaeota. It acts as a proton pump; that is, it captures light energy and uses it to move protons across the membrane out of the cell 
Bacteriorhodopsin is an integral membrane protein usually found in two-dimensional crystalline patches known as "purple membrane", which can occupy up to nearly 50% of the surface area of the archaeal cell.
Proteorhodopsin also known as pRhodopsinbis a family of over 50 photoactive retinylidene proteins, a larger family of transmembrane proteins that use retinal as a chromophore for light-mediated functionality, in this case, a proton pump
 
        
                    
             
        
        
        
Answer is C bc of the fact of diameter
        
             
        
        
        
Answer: A y B son correctas
Explanation:
 
        
             
        
        
        
Answer:
Answer is Ammonium sulfate.
Explanation:
The method of adding ammonium sulfate to a protein solution is known as precipitation. This is because the addition of ammonium sulfate will reduce or decrease the solubility of the protein. And as the ammonium sulfate is being increased, so also the solubility of the protein will be decreasing.
And at the long run, the protein will be precipitated. This is what is referred to as the 'salting out' procedure.