I think the awnser to your question is C
D. Cell membrane: surrounds a cell and allows substances to pass in and out
Answer:
Osmotic pressure and boiling point elevation
Explanation:
In the the osmotic pressure one can determine the molar mass of a solid by calculating the number of moles from the Morality formula which involves the volume of the solution.
In the boiling point elevation you can determine the number of moles of the solute in the solution by using the Molality formula.