The respiratory organs vary in different animals due
to their

Options

A. Nutrition
B. Habitat and level of organisation
C. Excretion
D. Reproduction

Answer

**Step-by-Step Solution:**

1. **Understanding the Question**: The question asks why respiratory organs vary among different animals. This implies that we need to explore the factors that influence the structure and function of these organs.

2. **Identifying Key Factors**: The options provided are nutrition, habitat and level of organization, excretion, and reproduction. Among these, habitat and level of organization are the most relevant to the respiratory organs.

3. **Exploring Habitat**:
- Animals can be categorized based on their habitat into aquatic (living in water) and terrestrial (living on land).
- Aquatic animals extract oxygen from water, which is dissolved in it. Therefore, they require specialized organs (like gills) to facilitate this process.
- Terrestrial animals, on the other hand, need to absorb atmospheric oxygen, necessitating different respiratory structures (like lungs).

4. **Considering Level of Organization**:
- The level of organization refers to how complex an organism is, which can be determined by its taxonomic classification.
- For example, a cockroach (a terrestrial organism) has a tracheal system, which is a network of tubes for gas exchange.
- An earthworm, also terrestrial, relies on cutaneous respiration, where gas exchange occurs directly through its skin.
- Mammals, which are more complex, have a well-developed respiratory system primarily consisting of lungs for efficient gas exchange.
- Amphibians like frogs can adapt their respiration based on their environment; they can use their skin for gas exchange in water and lungs when on land.

5. **Conclusion**: The variation in respiratory organs among different animals is primarily due to their habitat (aquatic vs. terrestrial) and their level of organization (complexity of the organism).

**Final Answer**: The respiratory organs vary in different animals due to their habitat and level of organization.

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