Final answer:
Acquired immunity is also known as active immunity, which can be naturally acquired by infection or artificially acquired by vaccination. Vaccines trigger artificially acquired active immunity by stimulating an immune response that leads to immunological memory, without causing sickness.
Step-by-step explanation:
Acquired Immunity and Vaccination
Another name for acquired immunity is active immunity. This form of immunity includes both naturally acquired active immunity, which occurs when a person is exposed to a live pathogen and develops a primary immune response, and artificially acquired active immunity, which results from vaccination. A vaccine introduces a killed or weakened pathogen or its components to stimulate an adaptive immune response without causing the full-blown disease. This leads to the development of immunological memory, preparing the immune system for future encounters with the same pathogen.
When asking which type of immunity is triggered by vaccination, the correct answer is A. Artificially acquired active immunity. Vaccination aims to prime the immune system by presenting it with antigens in a way that does not cause illness but still elicits a strong adaptive immune response, including the production of memory B cells and T cells.
Active immunity provides long-term protection as memory cells that develop after exposure to a pathogen or after vaccination can last for years, and sometimes for a lifetime. Thus, the activation of the immune system's adaptive response following vaccination not only staves off the initial sickness but offers ongoing protection against subsequent infections by the same pathogen.