Mutations are important for evolution because they remove excessive genetic variation allow individual organisms to evolve are the source of new genetic variation improve the survival of organisms

are the source of new genetic variation

Explanation:

Mutations are the alterations that occur in the genome of an organism.

The mutations can be caused either due to intrinsic factors such as replication error or extrinsic factors such as exposure to mutagens. Genetic variations are the differences in the genome sequence of individuals in a given population and it occurs mainly due to two processes :  

1. Mutation

2. Genetic recombiantion.