Modern birds rose in

Options

A. Palaeozoic
B. Coenozoic
C. Mesozoic
D. Archaeozoic

Answer

**Step-by-Step Solution:**

1. **Understand the Question**: The question asks in which geological era modern birds arose. The options provided are Palaeozoic, Cenozoic, Mesozoic, and Archaeozoic.

2. **Define Geological Eras**:
- **Palaeozoic Era**: Spanned from approximately 541 million years ago to 252 million years ago. This era saw the rise of major invertebrates, fishes, and amphibians.
- **Mesozoic Era**: Lasted from about 252 million years ago to 66 million years ago. This era is known for the dominance of reptiles, including dinosaurs.
- **Cenozoic Era**: Ranged from 66 million years ago to the present. It is often referred to as the age of mammals.
- **Archaeozoic Era**: Extended from about 3.8 billion years ago to 2.5 billion years ago, characterized by the earliest forms of life such as blue-green algae and bacteria.

3. **Analyze the Fossil Records**: The fossil records indicate that modern birds originated around 60 million years ago, which is shortly after the end of the Cretaceous period (the last period of the Mesozoic era) when dinosaurs became extinct.

4. **Determine the Correct Era**: Since modern birds arose after the extinction event that marked the end of the Mesozoic era, it can be concluded that modern birds rose during the Mesozoic era.

5. **Final Answer**: Based on the analysis, the correct answer is that modern birds rose in the **Mesozoic Era**.

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