Answer the following question given this paragraph: 

At the end of the Precambrian, a mass extinction occurred. In a mass extinction , the majority of species die out. The Precambrian mass extinction was the first of six mass extinctions that occurred on Earth. It’s not certain what caused this first mass extinction. Changes in Earth’s geology and climate were no doubt involved.


Q: What was the first mass extinction that occurred on earth?


A:
precambrian mass extinction