What does the Earth’s magnetic field reveal about the structure of the Earth’s layers? That the outer core is liquid.
That the mantle is solid.
That the mantle is liquid.
That the outer core is solid.

The mantle is solid.

Explanation:

The mantle is the mostly-solid bulk of Earth's interior. The mantle lies between Earth's dense, super-heated core and its thin outer layer, the crust. The mantle is about 2,900 kilometers thick, and makes up 84% of Earth's total volume.

answer; ///i believe that the correct answer is (a) specialized cells)

this is true, assuming that the allele is completely recessive and incomplete dominance is not a factor.