If there is a full article/story on this please post it.
The answer is cornea…..lens. Most bending of light entering
the eye is bent by the cornea. The lens of the other hand adjusts this bending
further, to focus it squarely on the retina. This is why the focal point of the
lens can be adjusted by changing its shape.
You could answer this question by Process of Elimination.
D) would be ruled out because this is a positive outcome.
B) would be ruled out because this is also a positive outcome.
C) is a weak distractor. A) is a better answer.
So your answer would probably be A)
Answer is (c). They move from higher concentration to lower one . This is called diffusion.