The role is to build up water with its dam to create a lake thus creating parts of the ecosystem it is also food for some animals.
What is this gizmo that you are talking about
. DNA replication is a highly accurate process, but mistakes can occasionally occur as when a DNA polymerase inserts a wrong base. Uncorrected mistakes may sometimes lead to serious consequences, such as cancer. ... Mutations: In this interactive, you can “edit” a DNA strand and cause a mutation.