Answer:
17. D) Hypothesis
18. Not accurate but it is precise 
19. D) precision
20. A) quantitive observation
21. B) Control
22. Volume.
hope this helps!
 
        
             
        
        
        
Answer:
Phospholipid bilayer
Explanation:
Liposomes are vesicles are spherical in shape. They consist of at least one phospholipd bilayer most especially phosphatidycholine. Liposomes are artficial vesicles similar to a membrane, because it has an hydrophilic core surrounded by a hydrophobic lipid bilayer.
Liposomes are artificial prepared and are used for the transportation of substances like drugs and nutrients between cell parts, outside of the cell and into the cell.  
In liposomal drug delivery, the liposome fuses with other internal cell membranes at the site of action and releases its liposomal content.
 
        
             
        
        
        
<span>They have setae covering their bodies. 
They have a one-way digestive system.</span>