Answer:
Nina has the flu and a high fever. Your immune system is displaying the second line of defense. This defense is part of the acquired immunity.
Step-by-step explanation:
Acquired immunity is the body's second line of defense and corresponds to a defense system that the body receives after it has acquired contact with an infectious agent, such as the influenza virus. An individual who has been infected by an invading agent is usually vaccinated. The vaccine content corresponds to the substances of the disease-causing pathogen, ie antigens. If the organism is attacked again by the microorganism, the body is already immune.