The most remarkable step in development of amphibians was

Options

A. Development of lungs
B. Transition from water to land
C. Releasing shelled eggs
D. Both (1) and (2)

Answer

### Step-by-Step Solution:

1. **Understanding Amphibians**: Amphibians are a class of animals that can live both in water and on land. They exhibit unique adaptations that allow them to thrive in these two different environments.

2. **Key Developmental Features**: The most remarkable step in the development of amphibians is their ability to respire through different structures at different life stages. In their larval stage, amphibians typically have gills for respiration, while in their adult stage, they develop lungs.

3. **Transition from Water to Land**: Amphibians are known as a transitional class between fish and reptiles. This means they possess characteristics that allow them to bridge the gap between aquatic and terrestrial life. This transition is significant in the evolutionary history of vertebrates.

4. **Egg Development**: Unlike reptiles, amphibians do not lay shelled eggs. Instead, they lay their eggs in water, which are usually surrounded by a jelly-like substance that provides protection against environmental stressors. This is an important reproductive adaptation for their aquatic lifestyle.

5. **Conclusion**: The most remarkable steps in the development of amphibians include:
- The development of lungs for respiration in adults.
- The transition from an aquatic to a terrestrial lifestyle.

6. **Final Answer**: Therefore, the correct answer is that the most remarkable step in the development of amphibians is both the development of lungs and the transition from water to land.