Which of the following statements best summarises the relationship between respiratory rate and body size related to animals?

Options

A. (a) larger the animal, higher the respiration rate
B. (b) smaller the animal, lower the respiration rate
C. (c) smaller the animals, higher the respiration rate
D. (d) size and respiratory rate are not related in any fashion

Answer

To determine the relationship between respiratory rate and body size in animals, we can follow these steps:

### Step 1: Understand the Concepts
- **Respiratory Rate**: This refers to the number of breaths taken per minute.
- **Body Size**: This refers to the physical size of the animal, which can be small or large.

### Step 2: Analyze the Relationship
- It is important to note that there is an inverse relationship between respiratory rate and body size. This means that as body size increases, the respiratory rate decreases.

### Step 3: Compare Smaller and Larger Animals
- **Smaller Animals**: They tend to have a higher respiratory rate. This is because they have a higher metabolism, which requires them to take in oxygen more frequently to support their energy needs.
- **Larger Animals**: They generally have a lower respiratory rate. Their metabolism is slower, and they can afford to take fewer breaths because their bodies are larger and require less oxygen relative to their size.

### Step 4: Explain the Metabolic Needs
- Smaller animals have a faster metabolism, which means they convert energy more quickly and need more oxygen in a shorter amount of time. This leads to a higher respiratory rate.
- Larger animals, on the other hand, have a slower metabolism, which means they require oxygen less frequently, resulting in a lower respiratory rate.

### Step 5: Consider the Bergmann's Rule
- The relationship between body size and respiratory rate can also be explained through Bergmann's Rule, which states that larger animals are found in colder environments, while smaller animals are found in warmer regions. This is linked to their metabolic rates and energy needs.

### Step 6: Evaluate the Options
- Now, let's evaluate the provided options:
- **A**: Larger the animal, higher the respiration rate. (Incorrect)
- **B**: Smaller the animal, lower the respiration rate. (Incorrect)
- **C**: Smaller the animals, higher the respiration rate. (Correct)
- **D**: Size and respiration rate are not related. (Incorrect)

### Conclusion
- The best statement that summarizes the relationship between respiratory rate and body size related to animals is **C: Smaller the animals, higher the respiration rate**.

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