An era "age of birds and mammals" is :

Options

A. Mesozoic
B. Palaeozoic
C. Cenozoic
D. Cretaceous

Answer

To answer the question "An era 'age of birds and mammals' is:", we will evaluate the given options step by step.

### Step 1: Understand the Options
We have four options to consider:
1. Mesozoic
2. Paleozoic
3. Cenozoic
4. Cretaceous

### Step 2: Analyze Each Era
- **Mesozoic Era**: This era is often referred to as the "Age of Reptiles" because it was dominated by dinosaurs and other reptiles. Therefore, this option is incorrect.

- **Paleozoic Era**: This era is known as the "Era of Ancient Life." It includes the emergence of many life forms but is not specifically known for birds and mammals. Thus, this option is also incorrect.

- **Cenozoic Era**: This is the era that follows the Mesozoic and is indeed referred to as the "Age of Birds and Mammals." This era is characterized by the dominance of mammals and birds after the extinction of the dinosaurs. Hence, this option is correct.

- **Cretaceous Period**: This is actually a period within the Mesozoic Era, specifically the last period of the age of dinosaurs. Therefore, this option is incorrect.

### Step 3: Conclusion
After analyzing all the options, we conclude that the correct answer is:
**Cenozoic Era** is the "age of birds and mammals."

### Final Answer
The era known as the "age of birds and mammals" is the **Cenozoic Era**.

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