Final answer:
Immunity is indeed acquired after an immunizing event, which can occur naturally or through immunization such as vaccination. Active immunity involves an individual's own immune response while passive immunity involves the transfer of antibodies from another individual.
Step-by-step explanation:
The statement that immunity is acquired only after an immunizing event is True. Immunity to pathogens can indeed be acquired by the active development of an immune response in the infected individual, which often happens after a natural infection with a pathogen, or through the passive transfer of immune components from an immune individual to a nonimmune one, such as when a mother transfers antibodies to her baby through breast milk.
Additionally, active immunity can result from immunization, which is the deliberate exposure to a pathogen in a controlled manner, such as via vaccination. In contrast to active immunity, passive immunity involves the transfer of antibodies from an immune individual to one that is not immune, providing immediate but temporary protection.
It's important to note that humans are born with innate immunity, which can respond quickly to pathogens, but the adaptive or acquired immune response, which includes T cells and B cells, takes days or weeks to become established. This acquired immunity is more specific and also involves a memory component, providing long-term protection from the same type of pathogen upon reexposure.