Which of the following is not a characteristic feature of sponges?

Options

A. Cellular level of organisation
B. Presence of ostia
C. Intracellular digestion
D. Body supported by chitin

Explanation

To determine which of the following is not a characteristic feature of sponges, we will analyze each option provided:

1. **Cellular level of organization**:
- Sponges are indeed characterized by a cellular level of organization. They are composed of different types of cells that do not form true tissues. This is a fundamental feature of sponges.

2. **Presence of ostea**:
- Sponges are known for their porous bodies, which contain numerous small openings called ostea. These ostea allow water to flow into the sponge, facilitating feeding and respiration. This is a characteristic feature of sponges.

3. **Intracellular digestion**:
- Sponges perform digestion at the cellular level, meaning that food particles are taken in by individual cells and digested internally. This is another characteristic feature of sponges.

4. **Body supported by chitin**:
- Chitin is a structural component found in the cell walls of fungi and in the exoskeletons of arthropods. However, sponges do not have chitin as a structural support. Instead, their bodies are supported by calcium carbonate or silica structures. Therefore, this statement is not true for sponges.

Based on this analysis, the option that is not a characteristic feature of sponges is:

**D. Body supported by chitin.**

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