Which statement is true about the immune system?

• A. The body's defense against illness
• B. A digestive organ
• C. No role in disease prevention
• D. Active only in childhood

Answer: (A)

The immune system is the body’s defense against illness. It protects us by recognizing invaders such as bacteria, viruses, and fungi, and by coordinating a response to remove them. This protection starts at barriers like the skin and mucous membranes that block entry, and then relies on a range of cells and processes. Innate immunity provides a quick, general defense with cells that attack invaders and promote inflammation. Adaptive immunity takes longer to respond but targets specific pathogens and creates memory so we fight future infections more effectively. Together, these systems work to prevent disease and help the body recover when infection occurs, which is why that statement is true.

It’s not a digestive organ, so it doesn’t have the roles of the stomach or intestines. It does play a crucial part in disease prevention, not only in childhood but throughout life, adapting as we’re exposed to new pathogens.