Mutations are changes in the DNA of an organism. Changes caused by mutations can affect the structure and function of different proteins in the body. Three changes caused by mutations are described below. Having two different colored eyes is caused by a mutation that results in increased or decreased pigmentation in one of the eyes. While this mutation affects the coloration of the eye, it does not affect how the eye functions. Cystic fibrosis is caused by the mutation of a protein in the lungs that causes a sticky mucus to build up in the lung tissue. This build up of mucus can make it difficult for a person to breathe. Bone density can be affected by a mutation. This mutation can cause very dense bones that are almost unbreakable. What is true about mutations in organism? 華 ОА. Changes caused by mutations always have positive effects on an organism. ОВ. Changes caused by mutations always have negative effects on an organism. OC. Changes caused by mutations never have an effect on an organism's cells. OD Changes caused by mutations can be harmful, beneficial, or neutral to an organism.​