Mammals have evolved from

Options

A. Birds
B. Reptiles
C. Amphibians
D. None of the above

Answer

**Step-by-Step Solution:**

1. **Understanding the Question:** The question asks about the evolutionary origin of mammals.

2. **Identifying the Options:** The options provided are:
- 1) Fish
- 2) Reptiles
- 3) Amphibians
- 4) None of the above

3. **Researching Evolutionary Lineage:** Mammals are believed to have evolved from reptiles. More specifically, they evolved from a group of reptiles known as therapsids during the Triassic period.

4. **Time Frame of Evolution:** This evolutionary transition occurred approximately 252 million to 201 million years ago.

5. **Understanding Therapsids:** Therapsids are a subgroup of reptiles, and they are significant in the evolutionary lineage leading to mammals.

6. **Identifying Key Groups:** Within the therapsids, the cynodonts are particularly important as they are the group that eventually gave rise to true mammals around 225 million years ago during the late Triassic period.

7. **Conclusion:** Based on the evolutionary lineage and the information gathered, the correct answer to the question "Mammals have evolved from" is **Reptiles**.

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