Question

Development of which trait freed land vertebrates from water.

• A. Four appendages
• B. Four chambered heart
• C. Cleidoic egg
• D. Lungs

Answer 1

Answer: (C)

Cleidoic egg

The evolution of cleidoic (shelled) was a significant evolutionary step, as it allowed eggs to be laid on land without drying out. Animals able to lay shelled eggs are called amniotes. As the eggs no longer need to be laid in water, it was also possible to eliminate the vulnerable 'tadpole' stage of life. With the shelled egg, land animals evolved into a wide range of primitive reptiles.

So, the correct option is 'cleidoic egg'.