Answer:
losing their hind-limbs, growing a flat tail, developing flippers and streamlining their bodies.
Explanation:
I can't see the well but chemical changes happen when a substance combines with another to form a new substance. These processes are called chemical reactions and are not reversible except if you do more chemical reactions... So the well that is changing it's state of matter should be the one undergoing a chemical change. For, example boiling or freezing
<span>The skeleton is made up of Cartilage</span>
The answer would be Fertilized egg
