The most unique mammalian characteristic is the:-

Options

A. Mammary glands
B. Internal fertilisation
C. Warm blooded body
D. Heart is four chambered

Answer

**Step-by-Step Solution:**

1. **Understanding the Question**: The question asks for the most unique characteristic of mammals from the given options.

2. **Analyzing the Options**:
- **Memory glands**: These are specialized glands found in female mammals that produce milk for nourishing their young.
- **Internal fertilization**: This is a reproductive process where fertilization occurs inside the female's body. It is not unique to mammals as it is also found in birds and some reptiles.
- **Warm-blooded body**: This refers to the ability to maintain a constant body temperature regardless of the environment. While mammals are warm-blooded, this characteristic is also present in birds.
- **Heart is four chambered**: A four-chambered heart is a feature of both mammals and birds, making it not unique to mammals.

3. **Identifying the Unique Characteristic**: Among the options, memory glands are the only feature that is unique to mammals. They are modified sweat glands that are specifically adapted for milk production.

4. **Conclusion**: Therefore, the correct answer is **memory glands**.

**Final Answer**: The most unique mammalian characteristic is the **memory glands**.

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