Man wears gloves and has protective clothing
        
                    
             
        
        
        
Solution
Cut open an onion.
Use forceps to peel a thin layer of epidermis from the inside.
Lay the layer of epidermis on a microscope slide.
Add a drop of iodine solution to the layer.
Carefully place a coverslip over the layer.
Observe it under a microscope to see onion cells.
        
             
        
        
        
<span>The answer to 10 is A as liquids expand with an increase in temperature. 12. Not able to answer. The answer to 17 is A as a the two different metals expand and contract at different rates when heated and cooled.</span>