Which of the following best describes the key discovery that advanced efforts to control infectious diseases?

• A. Recognition that the immune system can develop specific memory against pathogens
• B. Discovery that antibiotics are effective against all types of infections, including viral
• C. Understanding that all diseases are caused by environmental toxins
• D. Realization that handwashing alone can eliminate all infectious diseases

Answer: (A)

Verified step by step guidance

1. Step 1: Understand the context of infectious disease control by reviewing major historical advances in microbiology and medicine.
2. Step 2: Evaluate each option by considering its scientific accuracy and impact on disease control efforts.
3. Step 3: Recognize that antibiotics are effective primarily against bacterial infections, not viral infections, so the statement about antibiotics being effective against all types of infections is incorrect.
4. Step 4: Understand that while environmental toxins can cause some diseases, not all diseases are caused by them, so that option is inaccurate.
5. Step 5: Appreciate that handwashing is a critical infection control measure but does not eliminate all infectious diseases, whereas the immune system's ability to develop specific memory against pathogens is fundamental to long-term immunity and vaccine development, making it the key discovery.