List periods of Paleozoic era.

Answer

To answer the question about the periods of the Paleozoic era, we can follow these steps:

### Step-by-Step Solution:

1. **Understanding the Geological Time Scale**: The geological time scale is divided into eons, eras, periods, epochs, and ages. The Paleozoic era is one of the major divisions of the geological time scale.

2. **Identifying the Paleozoic Era**: The Paleozoic era spans from approximately 541 million years ago to about 252 million years ago. It is known for the emergence of a diverse range of life forms.

3. **Listing the Periods**: The Paleozoic era is divided into six distinct periods. These periods, in chronological order from oldest to youngest, are:
- **Cambrian** (541 - 485 million years ago)
- **Ordovician** (485 - 444 million years ago)
- **Silurian** (444 - 419 million years ago)
- **Devonian** (419 - 359 million years ago)
- **Carboniferous** (359 - 299 million years ago), which is further divided into:
- **Mississippian** (359 - 323 million years ago)
- **Pennsylvanian** (323 - 299 million years ago)
- **Permian** (299 - 252 million years ago)

4. **Final List of Periods**: Therefore, the complete list of the periods of the Paleozoic era is:
- Cambrian
- Ordovician
- Silurian
- Devonian
- Carboniferous (Mississippian and Pennsylvanian)
- Permian

### Final Answer:
The periods of the Paleozoic era are:
1. Cambrian
2. Ordovician
3. Silurian
4. Devonian
5. Carboniferous (Mississippian and Pennsylvanian)
6. Permian