Which term best completes: Vaccines work by stimulating what within the animal?

• A. Bacterial infections
• B. Antibiotic response
• C. Immunity
• D. Nutrient absorption

Answer: (C)

Vaccines work by stimulating immunity within the animal. They introduce harmless pieces or inactivated forms of a pathogen so the immune system can learn to recognize it. This trains specialized immune cells to respond quickly and produce specific antibodies, creating memory that protects against future infections. When the real pathogen is encountered later, the immune system can mount a rapid and effective defense, reducing disease risk.

The other ideas don’t fit because vaccines don’t cause bacterial infections themselves, they don’t create an antibiotic response (antibiotics are medicines used to treat infections, not part of how vaccines work), and they don’t influence nutrient absorption. The goal of vaccination is to build immunity.