What type of immunity is demonstrated by having an elevated temperature during an infection?

The presence of an elevated temperature during an infection is primarily indicative of innate immunity. Innate immunity is the first line of defense against pathogens and includes natural barriers such as skin and mucous membranes, as well as physiological responses like fever. When the body detects an infection, it can elevate its temperature as a response to inhibit the growth of pathogens and enhance the activity of immune cells.

Fever is a non-specific immune response that occurs as a result of the release of pyrogens, which act on the hypothalamus to increase body temperature. This response is crucial for the body to create an environment that is less favorable for the infecting organism and to ramp up the activity of immune components.

In contrast, adaptive immunity involves a more specific response to pathogens that the body has encountered before, typically involving B and T lymphocytes and the formation of antibodies. Acquired immunity generally refers to immunity that develops after exposure to a pathogen or its products, either through natural infection or vaccination. Passive immunity provides immediate protection through the transfer of antibodies from one individual to another, but does not involve a fever response.

Thus, the elevated temperature during an infection reflects an innate immune response, making it the correct choice.