Which of the following statements about the impact of animal research is true?

• A. It contributed to insulin.
• B. It contributed to pacemakers.
• C. It contributed to polio vaccine development timing.
• D. All of the above.

Answer: (D)

Animal research has shown tangible benefits across major medical advances. In the insulin story, experiments in dogs demonstrated that a pancreatic hormone could control blood glucose, paving the way for insulin therapy in people with diabetes. For pacemakers, animal models helped validate how electrical stimulation could reliably pace the heart and allowed development of safe implantable devices. Regarding polio, preclinical work in primates and other animals helped map the disease, test vaccine approaches, and set timelines for human trials, influencing when a safe vaccine could be rolled out. Taken together, each example reflects a real impact of animal research, so all of these are true.