In the context of immunity, infection and disease are not the same thing because:

• A. infection only happens after the body has developed immunity
• B. infection and disease are interchangeable terms describing the same process
• C. infection refers to the invasion and multiplication of microorganisms in the body, while disease occurs only when this invasion leads to tissue damage and symptoms
• D. disease always occurs without the presence of any microorganisms

Answer: (C)

Verified step by step guidance

1. Understand the definitions of the key terms: 'infection' and 'disease'. Infection is the process where microorganisms invade and multiply within the body.
2. Recognize that 'disease' refers to the condition that arises when the infection causes damage to tissues and results in symptoms.
3. Note that infection can occur without causing disease if the immune system controls or eliminates the microorganisms before tissue damage happens.
4. Distinguish that infection and disease are not interchangeable; infection is the presence of microbes, while disease is the manifestation of symptoms due to tissue damage.
5. Conclude that immunity can prevent disease even if infection occurs, highlighting why infection and disease are different concepts in immunity.