Which type of immunity is represented by skin, lactic acid secretions, stomach acidity, and the motion of cilia?

Which type of immunity is represented by skin, lactic acid secretions, stomach acidity, and the motion of cilia?

• A. Innate
• B. Cross
• C. Adaptive
• D. Auto

Answer: (A)

Innate immunity is being tested. These components are classic first-line, non-specific defenses that help block pathogens without needing prior exposure. The skin acts as a physical barrier to entry. Lactic acid secretions and stomach acidity create harsh chemical environments that inhibit or kill microbes. The motion of cilia in the airways helps clear inhaled pathogens by moving mucus upward and out of the respiratory tract. Because these defenses respond quickly and broadly to many different invaders, they fit the innate category. Adaptive immunity, in contrast, involves targeted responses by B and T cells and generates memory after exposure, which these physical and chemical barriers do not rely on. Cross immunity involves protection specific to related pathogens but isn’t described by these general barriers. Autoimmunity is about the immune system attacking the body’s own tissues, not about these protective barriers.

Innate immunity is being tested. These components are classic first-line, non-specific defenses that help block pathogens without needing prior exposure. The skin acts as a physical barrier to entry. Lactic acid secretions and stomach acidity create harsh chemical environments that inhibit or kill microbes. The motion of cilia in the airways helps clear inhaled pathogens by moving mucus upward and out of the respiratory tract. Because these defenses respond quickly and broadly to many different invaders, they fit the innate category.

Adaptive immunity, in contrast, involves targeted responses by B and T cells and generates memory after exposure, which these physical and chemical barriers do not rely on. Cross immunity involves protection specific to related pathogens but isn’t described by these general barriers. Autoimmunity is about the immune system attacking the body’s own tissues, not about these protective barriers.