[Solved] A mammalian expression cassette used to produce an exogenous gene in a virus vector must have which of the following components? A) Splicing signals. B) Strong enhancer. C) Polyadenylation signal D) Translational leader sequence E) All of the above are correct. Screening Tools: Screening tools are instruments or tests used to identify the presence of diseases, conditions, or risk factors in individuals who do not yet show symptoms. Occult Blood: Blood that is not visible to the naked eye, typically detected through specific medical tests in stool, which can indicate gastrointestinal issues. Specific Gravity: The ratio of dissolved substances in a solvent as compared with the ratio of dissolved substances in distilled water, most commonly comparing the ratio of dissolved substances in a urine specimen with distilled water. Reagent Strips: Test strips used for urinalysis or other tests that change color in response to various conditions or the presence of specific substances.