Which of the following does not pertain to a deuterostome?

Options

A. Blastopore is associated with the anus
B. Spiral cleavage
C. Enterocoelom
D. Echinoderms and chordates

Explanation

To determine which of the following does not pertain to a deuterostome, we need to analyze the provided options based on the characteristics of deuterostomes.

### Step-by-Step Solution:

1. **Understanding Deuterostomes**:
- Deuterostomes are a group of animals characterized by the development of the anus from the blastopore, which is the first opening that forms during embryonic development. The mouth develops later from a different opening.

2. **Analyzing Each Option**:
- **Option A**: "Blastopore is associated with the anus."
- This statement is true for deuterostomes, as the blastopore indeed becomes the anus. Therefore, this option pertains to deuterostomes.

- **Option B**: "Spiral cleavage."
- This statement is not true for deuterostomes. Deuterostomes exhibit indeterminate cleavage (also known as mosaic cleavage), where the fate of the cells is not determined early on. Spiral cleavage is characteristic of protostomes, not deuterostomes.

- **Option C**: "Enterocoelome."
- This statement is true for deuterostomes. Enterocoely refers to the formation of the coelom from the gut (enteron) and is a feature of deuterostomes like echinoderms and chordates.

- **Option D**: "Echinoderms and chordates."
- This statement is also true for deuterostomes, as both echinoderms (like starfish) and chordates (like vertebrates) are classified as deuterostomes.

3. **Conclusion**:
- The only option that does not pertain to deuterostomes is **Option B: Spiral cleavage**.

### Final Answer:
**The correct answer is Option B: Spiral cleavage.**

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