MCAT Biology Question 42: Answer and Explanation
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Question: 42
12. Neurofibromatosis type I, or von Recklinghausen's disease, is a disorder that causes formation of tumors in multiple nervous system structures as well as the skin. While all cells carry the same mutation on chromosome 17, selective transcription of the genome appears to cause the most significant tumorogenesis in which of the following primary germ tissue layers?
- A. Ectoderm
- B. Mesoderm
- C. Endoderm
- D. Notochord
Correct Answer: A
Explanation:
Here, the mutation affects the skin and the nervous system, both of which are derived from ectoderm. The other germ tissue layers do not lead to skin or nervous system formation, eliminating choices (B) and (C). The notochord is not actually a primary germ tissue layer, and thus cannot be an answer to the question, eliminating choice (D).