Which one of the following is NOT a characteristic of phylum Annelida
(a) Closed circulatory system
(b) Segmentation
(c) Pseudocoelom
(d) Ventral nerve cord

Options

A. Closed circulatory system
B. Segmentation
C. Pseudocoelom
D. Ventral nerve cord

Answer

To determine which option is NOT a characteristic of phylum Annelida, we will analyze each option one by one.

1. **Closed Circulatory System**:
- Annelids, such as earthworms, have a closed circulatory system. This means that their blood is contained within vessels, allowing for efficient transport of nutrients and gases. Therefore, this is a characteristic of Annelida.

2. **Segmentation**:
- A defining feature of phylum Annelida is metameric segmentation. This means that their bodies are divided into repeated segments, which is a key characteristic of annelids. Thus, this option cannot be the answer.

3. **Pseudocoelom**:
- Annelids possess a true coelom, which is a body cavity completely lined by mesoderm. In contrast, a pseudocoelom is a body cavity that is not completely lined by mesoderm. Since annelids do not have a pseudocoelom, this option is a strong candidate for being the correct answer.

4. **Ventral Nerve Cord**:
- Annelids have a ventral nerve cord, which is part of their nervous system. This is indeed a characteristic of the phylum, so this option cannot be the answer.

Based on the analysis, the option that is NOT a characteristic of phylum Annelida is:

**(c) Pseudocoelom**