Practice TEAS Science Test Related

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From which of the following germ layers does the nervous system develop?

  • A. Ectoderm
  • B. Endoderm
  • C. Gastroderm
  • D. Mesoderm
Correct Answer: A

Rationale: The correct answer is A: Ectoderm. The nervous system develops from the ectoderm, which is the outermost of the three germ layers. The ectoderm gives rise to structures such as the skin, hair, nails, and the entire nervous system. Choices B, C, and D are incorrect because the endoderm gives rise to the lining of the gut and associated organs, the gastroderm is not a recognized germ layer, and the mesoderm forms structures like muscles, bones, blood, and the circulatory system, but not the nervous system.