Lower vertebrate in which neural organisation is very simple & composed of netwrk of neurons is

Answer

**Step-by-Step Solution:**

1. **Understanding the Question**: The question asks for a lower vertebrate that has a simple neural organization composed of a network of neurons.

2. **Defining Neural Organization**: Neural organization refers to the arrangement and functioning of neurons, which are specialized cells responsible for transmitting signals in the nervous system.

3. **Identifying Lower Vertebrates**: Lower vertebrates include organisms such as fish, amphibians, and some invertebrates. However, the term "lower vertebrate" often refers to simpler organisms within the vertebrate classification.

4. **Characteristics of Lower Vertebrates**: Lower vertebrates typically have a simpler neural structure compared to higher vertebrates, which have more complex brains and nervous systems.

5. **Examples of Simple Neural Organization**: Among the lower vertebrates, organisms like hydra are noted for their simple neural organization. However, it is important to note that hydra is technically classified as an invertebrate, not a vertebrate.

6. **Conclusion**: The organism that fits the description of having a simple neural organization composed of a network of neurons is hydra, despite it being an invertebrate.

**Final Answer**: Hydra (though it is an invertebrate, it exemplifies simple neural organization).

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