Think about it, they survived a billion years, through great swings in climate, over hundreds of millions of years, lived through all the five great mass extinction events, where the dinosaurs went extinct and the poor little trilobites and countless other forms of life that we don't even know existed.
Imagínense, sobrevivieron durante millones de años soportando grandes cambios climáticos durante cientos de miles de años, sobrevivieron a las cinco extinciones masivas en las que los dinosaurios y los pobres minúsculos trilobites e innumerables desconocidas formas de vida se extinguieron.