Origin of mammal-like reptiles occurred in

Options

A. Triassic period
B. Permian period
C. Jurassic period
D. Tertiary period

Answer

To determine the origin of mammal-like reptiles, we need to analyze the geological periods and their significance in the evolution of life forms.

### Step-by-Step Solution:

1. **Understanding Geological Eras**: Life on Earth is divided into different geological eras: Azoic, Proterozoic, Paleozoic, Mesozoic, and Cenozoic. Each era has distinct life forms and evolutionary milestones.

2. **Identifying the Relevant Periods**: The question provides four options: Triassic period, Permian period, Jurassic period, and Tertiary period. We need to identify which of these periods is associated with the origin of mammal-like reptiles.

3. **Analyzing the Mesozoic Era**: The Triassic and Jurassic periods are part of the Mesozoic era, which is known as the age of reptiles, particularly dinosaurs. During this time, the dominant life forms were reptiles, and while primitive mammals existed, mammal-like reptiles were not the primary focus.

4. **Examining the Paleozoic Era**: The Permian period is part of the Paleozoic era. This era is significant for the evolution of early reptiles. The Permian period is recognized as the time when the first mammal-like reptiles emerged.

5. **Considering the Cenozoic Era**: The Tertiary period is part of the Cenozoic era, which is known as the age of mammals. By this time, mammal-like reptiles had already evolved into more advanced forms, so this period is not relevant to their origin.

6. **Conclusion**: Given the analysis, the origin of mammal-like reptiles occurred during the Permian period of the Paleozoic era. Therefore, the correct answer is the **Permian period**.

### Final Answer:
The origin of mammal-like reptiles occurred in the **Permian period**.