layla uses this model to show 2/6. refael uses this model to show 1/3. which statement best explains whether the models show that 2/6 and 1/3 are equivalent.

We can conclude that the correct option is the first one:
The models show that 2/6 is equivalent to 1/3 because both models have the same area shaded.
We can see that both shaded areas are the same, so 2/6 is equivalent to 1/3.
We can also do as follows, algebraically, to check this:
[tex]\frac{1}{3}\cdot\frac{2}{2}=\frac{2}{6}[/tex](We can also see that both models do not have the same number of parts shaded: in the first case, we have 2 shaded parts of 6, and, in the second, 1 of 3.)
Therefore, the correct option is the first one (as described above).