Question 23

Antibody defends the body.

Antibodies are specialized proteins produced by the immune system to identify and neutralize foreign invaders such as bacteria and viruses, thus playing a crucial role in defending the body.

A) Cortisol

Cortisol is a steroid hormone produced by the adrenal glands and is primarily involved in regulating metabolism, the immune response, and stress response. While it can influence immune system activity, it does not directly defend the body against pathogens.

B) Antibody

Antibodies are critical components of the immune system, specifically designed to recognize and bind to antigens on pathogens, facilitating their destruction. They are essential for adaptive immunity and provide targeted defense against infections.

C) Allergen

An allergen is a substance that triggers an allergic reaction, which is an inappropriate immune response. Allergens do not defend the body; instead, they can induce harmful reactions in sensitive individuals, indicating a failure of immune regulation.

D) Pathogen

Pathogens are microorganisms like bacteria, viruses, fungi, and parasites that cause disease. They are the targets of the immune system, not defenders; the immune system works to eliminate pathogens that invade the body.

Conclusion

Antibodies are the correct answer as they are specifically designed to protect the body from infections by neutralizing pathogens. In contrast, cortisol regulates immune functions without directly defending against invaders, while allergens and pathogens represent threats rather than defenders. Thus, antibodies are essential for maintaining health and preventing disease.