It is part of the cell theory
        
             
        
        
        
The stem of the plant should be cut at least three to four centimeters above the surface level.
The stem should be tightly fixed into the glass capillary.
All connection should be made air-tight by using paraffin.
Initial and final readings should be carefully noted.
        
             
        
        
        
Answer:
A is the answer to the question
 
        
             
        
        
        
the specimen ... is what’s it’s called