Blastopore is

Options

A. Opening of neural tube
B. Opening of Gastrocoel/Archenteron
C. Future anterior end of embryo
D. Found in Blastula

Answer

### Step-by-Step Solution:

1. **Understanding Fertilization**: The process begins with the fertilization of gametes, which leads to the formation of a diploid zygote.

**Hint**: Remember that fertilization is the fusion of male and female gametes.

2. **Cleavage Process**: After fertilization, the zygote undergoes rapid mitotic divisions known as cleavage. This results in the formation of a solid ball of cells called the morula.

**Hint**: Cleavage is important for increasing the number of cells without increasing the overall size of the embryo.

3. **Formation of Blastula**: The morula then develops into a hollow structure called the blastula, which is characterized by a fluid-filled cavity.

**Hint**: The blastula is a key stage in embryonic development, leading to the next phase.

4. **Gastrulation**: Following the blastula stage, the embryo undergoes gastrulation, leading to the formation of the gastrula. This stage involves the inward folding of cells.

**Hint**: Gastrulation is crucial as it establishes the three germ layers: ectoderm, mesoderm, and endoderm.

5. **Gastrocoel Formation**: In the gastrula, a cavity known as the gastrocoel (or archenteron) is formed. This cavity is essential for the development of the digestive system.

**Hint**: The gastrocoel is where the future digestive tract will develop.

6. **Identifying the Blastopore**: The opening of the gastrocoel is referred to as the blastopore. This structure is significant because it can develop into different parts of the digestive system depending on the organism.

**Hint**: The fate of the blastopore determines whether the organism is a protostome or a deuterostome.

7. **Protostomes vs. Deuterostomes**: If the blastopore develops into the mouth, the organism is classified as a protostome. If it develops into the anus, it is classified as a deuterostome.

**Hint**: Remember the key distinction: protostomes have the mouth forming first, while deuterostomes have the anus forming first.

### Conclusion:
The blastopore is the opening of the gastrocoel (archenteron) in the gastrula stage of embryonic development, and its future development determines whether an organism is a protostome or a deuterostome.