What major structure can be used to tell apart the embryos of acoelomates pseudocoelomates and coelomates?

answer; the correct answer is (beta)

b. lithosphere, asthenosphere, mesosphere   is the answer most likely

i believe the answer would be b. hope it : )

igneous rocks which formed by the crystallization of magma at the surface of the earth called extrusive rocks. they are characterized by fine-grained textures because the rapid cooling at or near the surface did not provide enough time for large crystals to grow.