The most primitive nervous system is found in

Options

A. Hydra
B. Amoeba
C. Sponge
D. Earthworm

Answer

**Step-by-Step Solution:**

1. **Understanding Nervous Systems in Animals**: The nervous system in animals has evolved over time. The complexity of the nervous system varies among different groups of animals.

2. **Identifying Primitive Nervous Systems**: The most primitive nervous systems are found in the earliest groups of animals. Invertebrates are the first animals to appear in the evolutionary timeline.

3. **Examining the Phylum Porifera**: The first invertebrates are members of the phylum Porifera (sponges). They do not have a nervous system; they lack neurons and sensory capabilities.

4. **Moving to Phylum Cnidaria**: The next group in the evolutionary line is the phylum Cnidaria, which includes organisms like Hydra. Members of this phylum possess a simple nervous system with neurons, allowing for basic sensation and response.

5. **Identifying Hydra**: Hydra, a member of Cnidaria, has a simple nerve net and is often cited as having one of the most primitive nervous systems among animals.

6. **Conclusion**: Therefore, the most primitive nervous system is found in Hydra, which is a member of the phylum Cnidaria.

**Final Answer**: The most primitive nervous system is found in Hydra.

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