Termination of gastrulation is indicated by

Options

A. obliteration of blastocoel
B. obliteration of archenteron
C. closure of blastopore
D. closure of neural tube

Explanation

**Step-by-Step Solution:**

1. **Understanding Gastrulation**: Gastrulation is a crucial phase in embryonic development that occurs after fertilization. It transforms the blastula, a hollow sphere of cells, into a three-layered structure known as the gastrula.

2. **Formation of Germ Layers**: During gastrulation, three primary germ layers are formed: ectoderm, mesoderm, and endoderm. These layers give rise to various tissues and organs in the developing embryo.

3. **Key Changes During Gastrulation**: The process of gastrulation involves significant morphological changes. The blastula undergoes invagination, where the cells move inward, leading to the formation of the gastrula.

4. **Termination of Gastrulation**: The termination of gastrulation is marked by specific events. One of the key indicators is the obliteration of the blastocoel (the fluid-filled cavity within the blastula). This obliteration signifies that the blastula has transitioned into a gastrula.

5. **Conclusion**: Therefore, the termination of gastrulation is indicated by the obliteration of the blastocoel.

**Final Answer**: The termination of gastrulation is indicated by the obliteration of the blastocoel.

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