Mutations in DNA may or may not result in a change in the phenotype of an organism. In which of the following situations will a mutation appear in the phenotype of an individual? a. The genetic code for protein synthesis has not been altered.

b. The mutation occurs in an organism which is past reproductive age.

c. The mutation is recessive and is present in one copy of the diploid gene.

d. The mutation is recessive and is present in both copies of the diploid gene.