How do mutations affect an organism? A. they may cause the development of a disease-causing allele B. they may cause the development of a more beneficial allele C. they, in some cases, may have no noticeable affect D. all of the above

Choose the best definition of allele. a. one of several possible versions of a gene, which each produce a different phenotype b. an organism that's purebred for a given trait c. the process of fertilizing a plant with pollen from another plant d. a set of genes that are located on the same chromosome and so are tightly linked