Age of invertebrates was

Options

A. Cambrian period
B. Ordovician period
C. Silurian period
D. Carboniferous period

Answer

### Step-by-Step Solution:

1. **Understanding the Question**: The question asks about the "Age of invertebrates," which refers to the geological period when invertebrates were most abundant and diverse.

2. **Identifying Geological Periods**: The options provided are:
- Cambrian period
- Ordovician period
- Silurian period
- Carboniferous period

3. **Analyzing Each Period**:
- **Cambrian Period**: Known for the "Cambrian Explosion," where many life forms, including early invertebrates, appeared. However, it is not solely characterized by invertebrates.
- **Ordovician Period**: This period is marked by a significant increase in the diversity and abundance of invertebrates, particularly marine life. It is often referred to as the "Age of Invertebrates."
- **Silurian Period**: This period saw the rise of some vertebrates and land plants, but invertebrates were still present.
- **Carboniferous Period**: Known for the development of extensive forests and the emergence of amphibians, but invertebrates were not the dominant group.

4. **Conclusion**: Based on the analysis, the Ordovician period is recognized as the "Age of Invertebrates" due to the significant diversity and abundance of invertebrate species during this time.

5. **Final Answer**: The correct answer is **Ordovician period (Option B)**.