Development which freed land vertebrates from water was

Options

A. Four appendages
B. Lungs
C. Cleidoic eggs
D. Four - chambered heart

Answer

**Step-by-Step Solution:**

1. **Understanding the Question**: The question asks about the development that allowed land vertebrates to move away from water environments.

2. **Identifying the Options**: The options provided are:
- 4 appendages (4 legs)
- Lungs
- Chelidoic eggs (shelled eggs)
- 4-chambered heart

3. **Analyzing Chelidoic Eggs**: The development of chelidoic eggs, or shelled eggs, was a significant evolutionary advancement. These eggs allowed vertebrates to reproduce on land without the risk of drying out, which was a major limitation when eggs were laid in water.

4. **Significance of Chelidoic Eggs**: Before the evolution of shelled eggs, eggs had to be laid in water to prevent desiccation. The presence of a protective shell allowed eggs to be laid on land, thus freeing the species from the dependency on aquatic environments.

5. **Impact on Life Cycle**: The ability to lay eggs on land eliminated the vulnerable tadpole stage that many amphibians experience. This made the life cycle of these animals less susceptible to predation and environmental hazards.

6. **Evolution of Primitive Reptiles**: With the advent of shelled eggs, land animals evolved into a variety of primitive reptiles, marking a significant transition in vertebrate evolution.

7. **Conclusion**: Therefore, the development that freed land vertebrates from water is the evolution of chelidoic eggs or shelled eggs.

**Final Answer**: The development which freed land vertebrates from water was chelidoic eggs (shelled eggs).

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