The neurenteric canal opens to the outside by

Options

A. Mouth
B. Blastopore
C. Neuropore
D. None of the above.

Answer

To solve the question regarding where the neurenteric canal opens to the outside, we can follow these steps:

### Step-by-Step Solution:

1. **Understanding the Neurenteric Canal**: The neurenteric canal is a structure that forms during embryonic development. It connects the neural tube to the gut.

2. **Identifying the Options**: The options given are:
- a. Mouth
- b. Blastopore
- c. Neuropore
- d. None of the above

3. **Analyzing Each Option**:
- **Option a (Mouth)**: The mouth is a structure that develops later in the embryonic stage and is not directly associated with the neurenteric canal.
- **Option b (Blastopore)**: The blastopore is the opening that forms during the early stages of embryonic development in many animals, particularly in lower invertebrates. It is associated with the formation of the gut.
- **Option c (Neuropore)**: The neuropore refers to the openings at the ends of the neural tube, which are not directly related to the neurenteric canal.
- **Option d (None of the above)**: This option suggests that none of the previous options are correct.

4. **Selecting the Correct Answer**: Given that the neurenteric canal connects to the gut and is associated with the early embryonic structure known as the blastopore, the correct answer is **Option b (Blastopore)**.

### Final Answer:
The neurenteric canal opens to the outside by **Option b: Blastopore**.

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