During embryonic development, what major event occurs during gastrulation?

• A. Development of the neural tube
• B. Formation of the three germ layers
• C. Initiation of limb bud formation
• D. Formation of the placenta

Answer: (B)

Verified step by step guidance

1. Understand the context of embryonic development: Gastrulation is a crucial phase in early embryonic development where significant cellular rearrangements occur.
2. Identify the key event during gastrulation: The formation of the three germ layers is the major event that defines gastrulation.
3. Clarify the role of the three germ layers: These layers are the ectoderm, mesoderm, and endoderm, which will give rise to all tissues and organs in the body.
4. Differentiate gastrulation from other developmental events: While the neural tube formation, limb bud initiation, and placenta formation are important, they occur at different stages of development.
5. Summarize the importance of gastrulation: This process sets the foundation for the complex body plan and organ development by establishing the primary layers from which all structures will develop.