Whale is a mammal because

Options

A. Its heart has four chambers
B. It is aquatic with stream lined body
C. It lays egg and produces milk
D. Diaphragm is found between thorax and abdomen .

Answer

**Step-by-Step Solution:**

1. **Understanding the Question**: The question asks why a whale is classified as a mammal. To answer this, we need to consider the characteristics that define mammals.

2. **Evaluating the Options**:
- **Option A: Its heart has four chambers**: While it is true that whales have a four-chambered heart, this characteristic is not exclusive to mammals. Birds also have a four-chambered heart, so this option does not uniquely identify whales as mammals.

- **Option B: It is aquatic with a streamlined body**: Many aquatic animals, including fish, have streamlined bodies. This characteristic does not specifically define mammals, so this option is also incorrect.

- **Option C: It lays eggs and produces milk**: Whales do produce milk, which is a characteristic of mammals, but they do not lay eggs; they give live birth. Therefore, this option is misleading and incorrect.

- **Option D: Diaphragm is found between thorax and abdomen**: The diaphragm is a muscle that is unique to mammals and plays a crucial role in respiration. This characteristic is exclusive to mammals and is a defining feature.

3. **Conclusion**: The correct answer is that whales are mammals because they possess a diaphragm, which is found between the thorax and abdomen. This is a unique characteristic that distinguishes mammals from other animal groups.

**Final Answer**: Whale is a mammal because the diaphragm is found between thorax and abdomen.

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