Which of the following best describes nonhuman animal models?

• A. They are surrogate models used to study human biology
• B. They are only used for veterinary studies
• C. They are exact replicas of human organs
• D. They are not used in biomedical research

Answer: (A)

Nonhuman animal models are surrogate systems used to study human biology in a living organism. They provide a whole-body context, letting researchers observe disease processes and responses to treatments across organs, tissues, and the immune system in ways not possible with isolated cells. This makes them especially valuable for exploring mechanisms, evaluating safety and dosing, and generating data that inform first-in-human studies. They are not exact replicas of human organs or physiology; species differences mean findings must be interpreted with care. They are not limited to veterinary studies and are indeed a central part of many biomedical research efforts. So, the best description is that they serve as surrogate models used to study human biology.