B. Newton's First Law, I'm pretty sure. The first states that an object in motion stays in motion, and an object at rest stays at rest until an outside force is applied, and that seems pretty relevant.
To what i see, the answer is....
C.
Answer:
It would be a physical change because you aren't changing to chemical properties of the glass, just the shape.
Answer: 
Explanation:
We know the total diameter of the cell (assumed spherical) is:

Then its total radius 
On the other hand, we know the thickness of the cell wall is
and its density is the same as water (
).
Since density is the relation between the mass
and the volume
:

The mass is:
(1)
Now if we are talking about this cell as a thin spherical shell, its volume will be:
(2)
Where 
Then:
(3)
(4)
Substituting (4) in (1):
(5)
(6)
Knowing
and
:
I think it’s B because we aren’t looking for Vf