When a host is exposed to antigens, which may be in the form of living or dead microbes or other proteins, antibodies are produced in the host body. This type of immunity is called______ immunity.

active

The correct answer is Option (2) -active

The type of immunity described, where antibodies are produced in response to exposure to antigens, is known as acquired immunity. Here's an explanation:

Acquired immunity refers to the immune response that develops over time as a result of exposure to foreign substances, such as microbes, toxins, or other antigens. This exposure can occur naturally through infection or artificially through vaccination.

Active immunity occurs when the immune system responds to the presence of antigens by producing antibodies and memory cells. These antibodies specifically target the antigens and work to neutralize or eliminate them from the body. Memory cells remain in the immune system and "remember" the specific antigen, providing long-lasting protection against future exposures to the same antigen. Active immunity can be further categorized into natural and artificial immunity, depending on whether the exposure to antigens occurs naturally or is induced through vaccination.

In contrast, passive immunity involves the transfer of pre-formed antibodies from one individual to another. This type of immunity provides immediate protection but does not result in the production of memory cells, so it is short-lived.

Therefore, in the context described, where antibodies are produced in response to exposure to antigens, the correct term is acquired immunity, specifically active immunity.