Planaria shows ___________ type of nervous system.

Options

A. nerve net.
B. ladder
C. ganglionated
D. brain

Answer

**Step-by-Step Solution:**

1. **Identify the Organism**: The question asks about the type of nervous system in Planaria, which is a type of flatworm belonging to the phylum Platyhelminthes.

2. **Understand the Nervous System Types**: There are various types of nervous systems in organisms, including:
- Nerve net (found in simpler organisms like cnidarians)
- Ganglionated nervous system (common in arthropods)
- Ladder-like nervous system (characteristic of flatworms)

3. **Describe the Ladder-like Nervous System**: In Planaria, the nervous system is described as ladder-like. This means that:
- There are two main longitudinal nerve cords running parallel to each other.
- Transverse nerves connect these longitudinal cords, resembling a ladder.

4. **Conclude the Answer**: Based on the characteristics of the nervous system in Planaria, we conclude that Planaria shows a ladder-like type of nervous system.

**Final Answer**: Planaria shows a ladder-like type of nervous system.

---