Answer:
Well one of the first changes it the tadpoles start growing legs. Then it will continue to grow, changing and changing as it goes. Then it will start to live on land, and it will live on land as a tiny frog until it is completely grown up.
Answer:

point mutation, change within a gene in which one base pair in the DNA sequence is altered. Point mutations are frequently the result of mistakes made during DNA replication, although modification of DNA, such as through exposure to X-rays or to ultraviolet radiation, also can induce point mutations