[Campbell Biology P.1017] Which of the following statements accurately describes a characteri... | Practice Question

Which of the following statements accurately describes a characteristic of passive immunity?

  • A: It provides long-term protection by inducing the recipient's own immune memory cells.
  • B: It is acquired when the body produces its own antibodies in response to antigen exposure, such as through vaccination.
  • C: It can be naturally transferred from a mother to her fetus via IgG antibodies crossing the placenta, offering immediate but temporary protection.
  • D: It results from the direct injection of a weakened pathogen or inactivated toxin to stimulate the recipient's adaptive immune response.

Explanation

Passive immunity involves the transfer of pre-formed antibodies from one individual to another, providing immediate but temporary protection. Natural passive immunity, as described in option C, occurs when maternal IgG antibodies cross the placenta to the fetus, offering protection while the infant's immune system develops. Options A, B, and D all describe aspects of active immunity, where the body's own immune system is stimulated to produce antibodies and memory cells.