In prokaryotes, the chromosomal DNA is typically

A. Mitosis: Mitosis is a mode of nuclear division characteristic of eukaryotic cells that have a defined nucleus and mitotic spindle; prokaryotes lack a nucleus and do not undergo mitosis.

B. Meiosis: Meiosis is a form of reductive nuclear division associated with sexual reproduction in eukaryotes; prokaryotes do not perform meiosis.

C. Binary fission: Binary fission is the asexual division process used by most prokaryotes, where the cell duplicates its DNA and divides into two genetically similar daughter cells.

D. All of the above: This would imply prokaryotes use mitosis and meiosis as well as binary fission; because mitosis and meiosis are eukaryotic processes, this option is not accurate.

A. Koch: Koch’s postulates are criteria for linking a microorganism to a disease and are unrelated to chemical carcinogenicity testing.

B. Ames: The Ames test uses bacteria to detect mutagenic potential of chemicals; because mutagens often correlate with carcinogens, the Ames test is widely used as a screen for carcinogenic potential.

C. Mutation: Mutation is a general term for DNA changes; while mutation assays detect genetic changes, the named specific screening test commonly used for carcinogenic potential is the Ames test.

D. Cancer: “Cancer test” is not a standard name for an assay used to screen chemicals for carcinogenic potential.

E. Iowa: Iowa is a proper noun (a U.S. state) and is not the name of a chemical carcinogenicity assay.