What is the name of the small, hard, benign skin growths caused by a virus that can be found on both skin and toads?

The correct answer is wart. Warts are small, hard growths on the skin that are caused by a viral infection, specifically by the human papillomavirus (HPV). They can appear anywhere on the body but are most commonly found on the hands, feet, and sometimes on mucous membranes. In addition to humans, certain types of warts can also appear on the skin of animals, including toads, showcasing their versatility across different species.

In contrast, a mole is a pigmented skin growth that usually appears brown or black and is not typically caused by a virus. A lesion is a broader term that encompasses any abnormal tissue change, including wounds, sores, or growths, but does not specifically refer to the benign growths caused by a virus. A callus is a thickened and hardened area of skin that develops in response to repeated friction or pressure, rather than a viral infection. Thus, warts are distinct in their viral origin and characteristic appearance.