They have sharp teeth up to 3 inches long and they are big
Answer:
Over our lifetime, our DNA can undergo changes or mutations that result in differences in the DNA sequence and may affect the proteins that are made. Mutations can occur as a natural consequence of errors in DNA replication or as a result of exposure to environmental factors such as smoking, sunlight or radiation.
Explanation:
The finches adapted over time to better suit their environment that they were in -- the size and shape of their beaks changed as a result of natural selection.