Answer:
The volcanoes provided, on the surface of the earth, the heat, water and the powerful cocktail of organic compounds (hydrogen sulphide, arsenic) that are at the beginning of life. In fact, the primitive organisms are for 2 billion years, fed by this soup, which makes scientists say that volcanic lakes are one of the possible cradles of life. The volcanoes not only kept life but also protected it in a distant time when the sun warmed our planet much less than today.
The intense performance of CO2 (carbon dioxide) volcanoes allowed the Earth's heat to fix itself permanently in our atmosphere. It is thanks to volcanic cataclysms that our planet was able to leave its frozen sphere state. In fact there are about 600 million years, an intense glacial period fell on the Earth, glaciers were present everywhere, the polar caps descended to the equator that covered the entire surface of the planet.