Which position of the three primary germ layers in the early embryo is correct?
A)Ectoderm on the inside,endoderm on the outside,and mesoderm in the middle
B)Endoderm on the inside,ectoderm on the outside,and mesoderm in the middle
C)Mesoderm on the inside,endoderm on the outside,and ectoderm in the middle
D)Ectoderm on the inside,mesoderm on the outside,and endoderm in the middle
E)Mesoderm on the inside,ectoderm on the outside,and endoderm in the middle

Question

Quizplus · Accepted Answer

During gastrulation, the endoderm is formed first and lines the inside of the embryo. The ectoderm, which will give rise to skin and nervous tissue, is formed next and lines the outside of the embryo. The mesoderm, which will give rise to muscle, bone, and connective tissue, is formed last and is located between the endoderm and ectoderm. Therefore, the correct position of the three primary germ layers in the early embryo is endoderm on the inside, ectoderm on the outside, and mesoderm in the middle. Choice B is the only option that follows this order.

Which Position of the Three Primary Germ Layers in the Early