If it isn’t a native breed it can overpopulate and destroy a stable ecosystem.
Mutations can affect an organism by changing its physical characteristics (or phenotype) or it can impact the way DNA codes the genetic information (genotype). When mutations occur they can cause termination (death) of an organism or they can be partially lethal.
That would be false as a solid is the only state of matter that has a fixed volume and mass, where as gasses and liquids are all flowing substances.