The correct option is 3: Crown gall disease The term "natural genetic engineering" is specifically used in biological literature to describe the mechanism of Crown gall disease. This disease is caused by the Gram-negative soil bacterium, Agrobacterium tumefaciens (also known as Rhizobium radiobacter). The bacterium possesses a large plasmid called the Tumor-inducing (Ti) plasmid, a segment of which, known as the Transfer-DNA (T-DNA), is naturally transferred into the wounded plant…Read More