Which of the following is most likely to have a much higher breathing rate ?

Options

A. man
B. dog
C. sparrow
D. fish

Answer

**Step-by-Step Solution:**

1. **Understanding Breathing Rate**: Breathing rate refers to the number of breaths taken in a minute. It is influenced by the size and metabolic rate of the organism.

2. **Size and Metabolic Rate Relationship**: Generally, smaller organisms tend to have a higher metabolic rate. This means they require more energy and therefore breathe more rapidly to meet their oxygen needs.

3. **Comparison of Organisms**: In the given options, we need to compare the sizes of the organisms:
- Fish (smallest)
- Sparrow (small)
- Dog (medium)
- Man (largest)

4. **Identifying the Organism with Highest Breathing Rate**: Since fish are the smallest among the listed organisms, they are expected to have the highest breathing rate due to their higher metabolic demands.

5. **Respiratory Structures**: Fish have gills which allow them to extract oxygen from water, while the other organisms (sparrow, dog, man) have lungs which are adapted for breathing air.

6. **Conclusion**: Based on the above reasoning, the organism most likely to have a much higher breathing rate is the fish.

**Final Answer**: Fish

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