The rate of heart beat per minute is highest in case of

Options

A. Elephant
B. Whale
C. Man
D. Mouse

Answer

### Step-by-Step Solution:

1. **Understanding Heartbeat**: A heartbeat is defined as one complete cycle of contraction and relaxation of the heart. This cycle is crucial for pumping blood throughout the body.

2. **Factors Affecting Heartbeat Rate**: The rate of heartbeat can be influenced by several factors, including:
- Availability of oxygen
- Body fitness
- Size of the organism
- Presence of drugs in the body

3. **Analyzing the Options**: The question provides four options: elephant, whale, man, and mouse. We need to determine which of these has the highest heartbeat rate.

4. **Comparing Heartbeat Rates**:
- **Mouse**: The smallest size among the options, with a heartbeat rate of approximately 400 to 500 beats per minute.
- **Man**: A medium-sized organism, with a heartbeat rate of about 72 beats per minute.
- **Elephant**: A large organism, with a heartbeat rate of around 25 to 30 beats per minute.
- **Whale**: The largest mammal, with the lowest heartbeat rate of about 10 beats per minute.

5. **Conclusion**: Based on the analysis of the heartbeat rates in relation to their sizes, the mouse has the highest heartbeat rate among the given options.

6. **Final Answer**: Therefore, the correct answer is **Option D: Mouse**.