Read the following passage and answer the question below. The human immune system is a complex network of cells, tissues, and organs that work together to defend the body against harmful invaders such as bacteria, viruses, and other pathogens. It operates on two main levels: the innate immune system, which provides a rapid but general response to any perceived threat, and the adaptive immune system, which develops a targeted response specific to a particular pathogen and can retain a memory of it for future encounters. This immune memory is the principle behind vaccination, which trains the immune system to recognize and fight a specific pathogen without the person having to experience the actual disease first. While the immune system is remarkably effective, it can also malfunction, leading to conditions such as autoimmune diseases, where the body mistakenly attacks its own healthy cells, or allergies, where the immune system overreacts to substances that are normally harmless. Researchers continue to study the immune system in hopes of developing better treatments for these disorders. Question: What is the passage primarily about?
- A. How the human immune system functions and what happens when it malfunctions ✓
- B. The discovery of antibiotics
- C. The process of digestion
- D. The structure of red blood cells
Correct answer
A. How the human immune system functions and what happens when it malfunctions
Explanation
The passage explains how the immune system works and describes disorders that arise from its malfunction.