Gene splicing can give rise to new varieties of farm animals that have only a partially understood genetic makeup. In addition to introducing the genes for whichever trait is desired, the technique can introduce genes governing the production of toxins or carcinogens, and these latter undesirable traits might not be easily discoverable. The statements above, if true, most strongly support which one of the following? ['Gene splicing to produce new varieties of farm animals should be used cautiously.', 'Most new varieties of farm animals produced by gene splicing will develop cancer.', 'Gene splicing is not effective as a way of producing new varieties of farm animals.', 'All toxin production is genetically controlled.']