Epithelial membranes are made from epithelial tissue attached to a layer of connective tissue. There are three types of epithelial membranes: mucous, which contain glands; serous<span>, which secrete fluid; and </span>cutaneous<span> which </span>makes<span> up the skin. </span>
        
             
        
        
        
Answer: Option B 
Explanation: The thin layer that forms the outer covering of the cell is known as the cell membrane. It is composed of the lipid bilayer which as embedded proteins. 
This membrane is selectively permeable which means it allows only specific molecules to pass through them.
The main function of cell membrane is to protect the cell from the outer environment and by the invasion of harmful bacteria and viruses.
 
        
                    
             
        
        
        
In the nucleus of a cell.