The functioning, but not the structure, of the central nervous system is vulnerable throughout the _____ period.

• A. germinal
• B. fetal
• C. critical
• D. embryonic

Answer: (B)

Verified step by step guidance

1. Understand the context of the question: The central nervous system (CNS) is a crucial part of the human body responsible for processing information and controlling activities. The question asks about the period during which the functioning of the CNS is vulnerable, not its structure.
2. Identify the different periods of prenatal development: The germinal period (first two weeks after conception), the embryonic period (weeks 3-8), and the fetal period (week 9 to birth). Each period has distinct characteristics and vulnerabilities.
3. Consider the development of the CNS: During the embryonic period, the structure of the CNS is forming, making it vulnerable to structural defects. However, the question focuses on the functioning, not the structure.
4. Analyze the fetal period: This is when the CNS continues to develop and mature, and the functioning becomes more complex. The CNS is particularly sensitive to external influences that can affect its functioning during this time.
5. Conclude that the functioning of the CNS is most vulnerable during the fetal period, as this is when the brain and nervous system are developing their functional capabilities, making them susceptible to various influences.